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‎LargestPerimeterTriangle/largest_perimeter_triangle.dart

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/*
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-* Largest Perimeter Triangle *-
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Given an integer array nums, return the largest perimeter of a triangle with a non-zero area, formed from three of these lengths. If it is impossible to form any triangle of a non-zero area, return 0.
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Example 1:
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Input: nums = [2,1,2]
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Output: 5
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Example 2:
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Input: nums = [1,2,1]
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Output: 0
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Constraints:
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3 <= nums.length <= 104
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1 <= nums[i] <= 106
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*/
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import 'dart:math';
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class A {
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// Runtime: 426 ms, faster than 80.00% of Dart online submissions for Largest Perimeter Triangle.
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// Memory Usage: 149.6 MB, less than 100.00% of Dart online submissions for Largest Perimeter Triangle.
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int largestPerimeter(List<int> nums) {
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nums.sort();
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for (int i = nums.length - 1; i > 1; --i)
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if (nums[i] < nums[i - 1] + nums[i - 2])
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return nums[i] + nums[i - 1] + nums[i - 2];
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return 0;
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}
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}
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class B {
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// Runtime: 514 ms, faster than 60.00% of Dart online submissions for Largest Perimeter Triangle.
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// Memory Usage: 150.2 MB, less than 20.00% of Dart online submissions for Largest Perimeter Triangle.
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//utility method to get max element at given index
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void swapToGetMax(List<int> nums, int index) {
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int max = 0, maxIndex = -1;
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for (int i = 0; i <= index; i++)
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if (max < nums[i]) {
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max = nums[i];
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maxIndex = i;
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}
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//actual swapping after finding max element in given range
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int temp = nums[index];
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nums[index] = max;
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nums[maxIndex] = temp;
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}
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int largestPerimeter(List<int> nums) {
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//if array has only 3 elements
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if (nums.length == 3) {
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if (nums[0] < nums[1] + nums[2] &&
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nums[1] < nums[0] + nums[2] &&
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nums[2] < nums[1] + nums[0])
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return nums[0] + nums[1] + nums[2];
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else
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return 0;
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}
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//for more than 3 elements, without doing explicit sorting
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int n = nums.length;
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//here we are putting max element at last index
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swapToGetMax(nums, n - 1);
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//here we are putting max element at second last index
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swapToGetMax(nums, n - 2);
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//here we are putting max element at third last index
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swapToGetMax(nums, n - 3);
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//in loop checking if nums[i]<nums[i-1]+nums[i-2] which this triplet will form the max perimeter
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for (int i = n - 1; i >= 2; i--) {
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if (nums[i] < nums[i - 1] + nums[i - 2])
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return nums[i] + nums[i - 1] + nums[i - 2];
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//if not then will find max element as (i-3)th largest element
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else if (i > 2) swapToGetMax(nums, i - 3);
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}
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return 0;
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}
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}
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class C {
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// Runtime: 596 ms, faster than 40.00% of Dart online submissions for Largest Perimeter Triangle.
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// Memory Usage: 150.3 MB, less than 20.00% of Dart online submissions for Largest Perimeter Triangle.
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int largestPerimeter(List<int> nums) {
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if (nums.length == 3) {
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if (nums[0] < nums[1] + nums[2] &&
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nums[1] < nums[0] + nums[2] &&
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nums[2] < nums[1] + nums[0])
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return nums[0] + nums[1] + nums[2];
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else
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return 0;
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}
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int n = nums.length;
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int maxi = 0;
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for (int i = 0; i < n - 2; i++) {
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for (int j = i + 1; j < n - 1; j++) {
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for (int k = j + 1; k < n; k++) {
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int a = nums[i];
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int b = nums[j];
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int c = nums[k];
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if (a < b + c && b < c + a && c < a + b) maxi = max(maxi, a + b + c);
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}
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}
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}
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if (maxi > 0) return maxi;
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return 0;
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}
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}
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class D {
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int largestPerimeter(List<int> nums) {
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//sort the vector
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nums.sort();
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//any triangle sum of smaller two side greater than 3rd side...so we check that condition, a+b>c where a<b<c
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int maxPerimeter = 0;
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for (int i = 0; i <= nums.length - 3; i++) {
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//check the triangle valid condition
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if (nums[i] + nums[i + 1] > nums[i + 2]) {
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maxPerimeter =
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max(maxPerimeter, nums[i] + nums[i + 1] + nums[i + 2]); //find max
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}
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}
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return maxPerimeter; //return the result
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}
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}
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class F {
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int largestPerimeter(List<int> nums) {
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nums.sort((a, b) => a - b);
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int i = nums.length - 1;
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while (i >= 0) {
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if (nums[i] < nums[i - 1] + nums[i - 2]) {
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return nums[i] + nums[i - 1] + nums[i - 2];
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} else {
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i--;
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}
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}
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return 0;
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}
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}

‎LargestPerimeterTriangle/largest_perimeter_triangle.go

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package main
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import "sort"
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func largestPerimeter(nums []int) int {
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sort.Slice(nums, func(i, j int) bool {
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return nums[i] > nums[j]
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})
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for i := 0; i < len(nums)-2; i++ {
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a := nums[i]
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b := nums[i+1]
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c := nums[i+2]
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if a < (b + c) {
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return a + b + c
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}
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}
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return 0
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}

‎LargestPerimeterTriangle/largest_perimeter_triangle.md

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# 🔥 Largest Perimeter Triangle 🔥 || 5 Solutions || Simple Fast and Easy || with Explanation
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## Solution - 1
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Before diving into code.. Let us recall the basic rule for lengths of sides of a triangle
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i.e, sum of any two sides of a triangle should be greater than its third side.
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Simply, a + b > c
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where a, b, c are sides of triangle
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Approach:
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Since we need the largest perimeter from the given nums. We sort the array and traverse from the end
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if nums[i] < nums[i-1] + nums[i-2], then
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we Stop and return the perimeter==> nums[i] + nums[i-1] + nums[i-2]
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if there is no values that satisfies the given condition then
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we return 0
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```dart
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class Solution {
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// Runtime: 426 ms, faster than 80.00% of Dart online submissions for Largest Perimeter Triangle.
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// Memory Usage: 149.6 MB, less than 100.00% of Dart online submissions for Largest Perimeter Triangle.
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int largestPerimeter(List<int> nums) {
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nums.sort();
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for (int i = nums.length - 1; i > 1; --i)
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if (nums[i] < nums[i - 1] + nums[i - 2])
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return nums[i] + nums[i - 1] + nums[i - 2];
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return 0;
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}
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}
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```
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## Solution - 2 Recursive
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```dart
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class Solution {
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// Runtime: 514 ms, faster than 60.00% of Dart online submissions for Largest Perimeter Triangle.
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// Memory Usage: 150.2 MB, less than 20.00% of Dart online submissions for Largest Perimeter Triangle.
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//utility method to get max element at given index
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void swapToGetMax(List<int> nums, int index) {
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int max = 0, maxIndex = -1;
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for (int i = 0; i <= index; i++)
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if (max < nums[i]) {
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max = nums[i];
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maxIndex = i;
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}
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//actual swapping after finding max element in given range
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int temp = nums[index];
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nums[index] = max;
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nums[maxIndex] = temp;
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}
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int largestPerimeter(List<int> nums) {
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//if array has only 3 elements
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if (nums.length == 3) {
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if (nums[0] < nums[1] + nums[2] &&
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nums[1] < nums[0] + nums[2] &&
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nums[2] < nums[1] + nums[0])
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return nums[0] + nums[1] + nums[2];
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else
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return 0;
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}
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//for more than 3 elements, without doing explicit sorting
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int n = nums.length;
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//here we are putting max element at last index
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swapToGetMax(nums, n - 1);
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//here we are putting max element at second last index
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swapToGetMax(nums, n - 2);
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//here we are putting max element at third last index
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swapToGetMax(nums, n - 3);
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//in loop checking if nums[i]<nums[i-1]+nums[i-2] which this triplet will form the max perimeter
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for (int i = n - 1; i >= 2; i--) {
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if (nums[i] < nums[i - 1] + nums[i - 2])
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return nums[i] + nums[i - 1] + nums[i - 2];
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//if not then will find max element as (i-3)th largest element
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else if (i > 2) swapToGetMax(nums, i - 3);
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}
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return 0;
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}
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}
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```
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## Solution - 3
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```dart
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class Solution {
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// Runtime: 596 ms, faster than 40.00% of Dart online submissions for Largest Perimeter Triangle.
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// Memory Usage: 150.3 MB, less than 20.00% of Dart online submissions for Largest Perimeter Triangle.
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int largestPerimeter(List<int> nums) {
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if (nums.length == 3) {
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if (nums[0] < nums[1] + nums[2] &&
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nums[1] < nums[0] + nums[2] &&
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nums[2] < nums[1] + nums[0])
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return nums[0] + nums[1] + nums[2];
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else
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return 0;
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}
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int n = nums.length;
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int maxi = 0;
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for (int i = 0; i < n - 2; i++) {
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for (int j = i + 1; j < n - 1; j++) {
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for (int k = j + 1; k < n; k++) {
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int a = nums[i];
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int b = nums[j];
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int c = nums[k];
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if (a < b + c && b < c + a && c < a + b) maxi = max(maxi, a + b + c);
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}
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}
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}
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if (maxi > 0) return maxi;
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return 0;
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}
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}
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```
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## Solution - 4
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```dart
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class Solution {
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int largestPerimeter(List<int> nums) {
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//sort the vector
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nums.sort();
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//any triangle sum of smaller two side greater than 3rd side...so we check that condition, a+b>c where a<b<c
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int maxPerimeter = 0;
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for (int i = 0; i <= nums.length - 3; i++) {
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//check the triangle valid condition
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if (nums[i] + nums[i + 1] > nums[i + 2]) {
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maxPerimeter =
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max(maxPerimeter, nums[i] + nums[i + 1] + nums[i + 2]); //find max
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}
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}
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return maxPerimeter; //return the result
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}
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}
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```
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## Solution - 5
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```dart
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class Solution {
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int largestPerimeter(List<int> nums) {
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nums.sort((a, b) => a - b);
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int i = nums.length - 1;
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while (i >= 0) {
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if (nums[i] < nums[i - 1] + nums[i - 2]) {
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return nums[i] + nums[i - 1] + nums[i - 2];
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} else {
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i--;
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}
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}
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return 0;
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}
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}
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```

‎README.md

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- [Palindrome Linked List](PalindromeLinkedList/palindrome_linked_list.dart)
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- [Increasing Triplet Subsequence](IncreasingTripletSubsequence/increasing_triplet_subsequence.dart)
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- [Shortest Word Distance](ShortestWordDistance/shortest_word_distance.dart)
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- [Largest Perimeter Triangle](LargestPerimeterTriangle/largest_perimeter_triangle.dart)
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## Reach me via
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