leetcode

Author: ayoubzulfiqar

README.md

@@ -48,6 +48,7 @@ This repo contain leetcode solution using DART and GO programming language. Most
 - [Design Circular Queue](DesignCircularQueue/design_circular_queue.dart)
 - [Satisfiability of Equality Equations](SatisfiabilityOfEqualityEquations/satisfiability_of_equality_equations.dart)
 - [Best Time to Buy and Sell Stock](BestTimeToBuyAndSellStock/best_time_to_buy_and_sell_stock.dart)
+- [Valid Palindrome](ValidPalindrome/valid_palindrome.dart)
 
 ## Reach me via
 

ValidPalindrome/valid_palindrome.dart

@@ -0,0 +1,108 @@
+/*
+
+ -* Valid Palindrome *-
+
+ A phrase is a palindrome if, after converting all uppercase letters into lowercase letters and removing all non-alphanumeric characters, it reads the same forward and backward. Alphanumeric characters include letters and numbers.
+
+Given a string s, return true if it is a palindrome, or false otherwise.
+
+
+
+Example 1:
+
+Input: s = "A man, a plan, a canal: Panama"
+Output: true
+Explanation: "amanaplanacanalpanama" is a palindrome.
+Example 2:
+
+Input: s = "race a car"
+Output: false
+Explanation: "raceacar" is not a palindrome.
+Example 3:
+
+Input: s = " "
+Output: true
+Explanation: s is an empty string "" after removing non-alphanumeric characters.
+Since an empty string reads the same forward and backward, it is a palindrome.
+
+
+Constraints:
+
+1 <= s.length <= 2 * 105
+s consists only of printable ASCII characters.
+
+
+*/
+
+class A {
+// Runtime: 580 ms, faster than 53.41% of Dart online submissions for Valid Palindrome.
+// Memory Usage: 147.8 MB, less than 32.95% of Dart online submissions for Valid Palindrome.
+  bool isPalindrome(String s) {
+    // replacing the whole string based on regex match
+    s = s.toLowerCase().replaceAll(RegExp("[^a-zA-Z0-9]"), "");
+    //building a new string and splitting it and turing into a single element and reversing it and than joining to build
+    // a single string
+    String t = s.toString().split("").reversed.join();
+    // if the it is same both are same than true otherwise false
+    return s == t;
+  }
+}
+
+class B {
+// Runtime: 576 ms, faster than 55.68% of Dart online submissions for Valid Palindrome.
+// Memory Usage: 144.7 MB, less than 77.27% of Dart online submissions for Valid Palindrome.
+  bool isPalindrome(String s) {
+    s = s.toLowerCase().replaceAll(RegExp("[^a-zA-Z0-9]"), "");
+    int left = 0, right = s.length - 1;
+
+    while (left < right) {
+      if (s[left] != s[right]) return false;
+
+      left++;
+      right--;
+    }
+
+    return true;
+  }
+}
+
+class C {
+// Runtime: 762 ms, faster than 11.36% of Dart online submissions for Valid Palindrome.
+// Memory Usage: 145.2 MB, less than 63.64% of Dart online submissions for Valid Palindrome.
+  bool isPalindrome(String s) {
+    s = s.toLowerCase().replaceAll(RegExp("[^a-zA-Z0-9]"), "");
+    int right = (s.length / 2).floor();
+    int left = s.length % 2 == 0 ? right - 1 : right;
+
+    while (left >= 0 && right < s.length) {
+      if (s[left] != s[right]) return false;
+
+      left--;
+      right++;
+    }
+
+    return true;
+  }
+}
+
+// Massive Range error
+class D {
+  bool isPalindrome(String s) {
+    bool isLetterOrDigit(String input) => RegExp(r'^[\w\d]$').hasMatch(input);
+
+    int i = 0, j = s.length - 1;
+
+    while (i < j) {
+      while (!isLetterOrDigit(s[i])) {
+        i++;
+      }
+      while (!isLetterOrDigit(s[j])) {
+        j--;
+      }
+      if (!(s[i++].toLowerCase() == s[j--].toLowerCase())) {
+        return false;
+      }
+    }
+    return true;
+  }
+}

ValidPalindrome/valid_palindrome.go

@@ -0,0 +1,96 @@
+package main
+
+func isPalindrome(s string) bool {
+	isD := func(r rune) bool {
+		return r >= '0' && r <= '9'
+	}
+	isA := func(r rune) bool {
+		return (r >= 'a' && r <= 'z') || (r >= 'A' && r <= 'Z')
+	}
+	is := func(r rune) bool {
+		return isA(r) || isD(r)
+	}
+
+	l := len(s)
+	lt := 0
+	rt := l - 1
+	var empty rune
+	for lt < rt {
+		var f rune
+		var l rune
+		for lt < rt {
+			if is(rune(s[lt])) {
+				f = rune(s[lt])
+				break
+			}
+			lt++
+		}
+		for lt < rt {
+			if is(rune(s[rt])) {
+				l = rune(s[rt])
+				break
+			}
+			rt--
+		}
+		switch {
+		case isA(f) && isD(l) || isD(f) && isA(l):
+			return false
+		case !(f-l == 32 || f-l == -32 || f-l == 0) && f != empty && l != empty:
+			return false
+		}
+		lt++
+		rt--
+	}
+	return true
+}
+
+func isPalindromes(s string) bool {
+	result := ""
+	for i := 0; i < len(s); i++ {
+		if isAlphaNumeric(string(s[i])) {
+			if isNum(string(s[i])) {
+				result += string(s[i])
+			}
+			if isUpperCase(string(s[i])) {
+				result += string(lowerCase(string(s[i])))
+			} else {
+				result += string(s[i])
+			}
+		}
+	}
+	return palindrom(string(result))
+}
+
+func isAlphaNumeric(s string) bool {
+	if ('0' <= s[0] && s[0] <= '9') || (s[0] >= 'a' && s[0] <= 'z') || (s[0] >= 'A' && s[0] <= 'Z') {
+		return true
+	}
+	return false
+}
+
+func isUpperCase(s string) bool {
+	if s[0] >= 'A' && s[0] <= 'Z' {
+		return true
+	}
+	return false
+}
+
+func isNum(s string) bool {
+	if s[0] >= '0' && s[0] <= '9' {
+		return true
+	}
+	return false
+}
+
+func lowerCase(s string) byte {
+	return s[0] - 'A' + 'a'
+}
+
+func palindrom(s string) bool {
+	for i := 0; i < len(s)/2; i++ {
+		if s[i] != s[len(s)-1-i] {
+			return false
+		}
+	}
+	return true
+}

ValidPalindrome/valid_palindrome.md

@@ -0,0 +1,66 @@
+# ✅ DART || 4 solutions || simple fast easy
+
+## Solution - 1
+
+```dart
+class Solution {
+// Runtime: 580 ms, faster than 53.41% of Dart online submissions for Valid Palindrome.
+// Memory Usage: 147.8 MB, less than 32.95% of Dart online submissions for Valid Palindrome.
+  bool isPalindrome(String s) {
+    // replacing the whole string based on regex match
+    s = s.toLowerCase().replaceAll(RegExp("[^a-zA-Z0-9]"), "");
+    //building a new string and splitting it and turing into a single element and reversing it and than joining to build
+    // a single string
+    String t = s.toString().split("").reversed.join();
+    // if the it is same both are same than true otherwise false
+    return s == t;
+  }
+}
+```
+
+## Solution - 2
+
+```dart
+class Solution {
+// Runtime: 576 ms, faster than 55.68% of Dart online submissions for Valid Palindrome.
+// Memory Usage: 144.7 MB, less than 77.27% of Dart online submissions for Valid Palindrome.
+  bool isPalindrome(String s) {
+    s = s.toLowerCase().replaceAll(RegExp("[^a-zA-Z0-9]"), "");
+    int left = 0, right = s.length - 1;
+
+    while (left < right) {
+      if (s[left] != s[right]) return false;
+
+      left++;
+      right--;
+    }
+
+    return true;
+  }
+}
+```
+
+## Solution - 3
+
+```dart
+class Solution {
+// Runtime: 762 ms, faster than 11.36% of Dart online submissions for Valid Palindrome.
+// Memory Usage: 145.2 MB, less than 63.64% of Dart online submissions for Valid Palindrome.
+  bool isPalindrome(String s) {
+    s = s.toLowerCase().replaceAll(RegExp("[^a-zA-Z0-9]"), "");
+    int right = (s.length / 2).floor();
+    int left = s.length % 2 == 0 ? right - 1 : right;
+
+    while (left >= 0 && right < s.length) {
+      if (s[left] != s[right]) return false;
+
+      left--;
+      right++;
+    }
+
+    return true;
+  }
+}
+```
+
+## [GitHub Link](https://github.com/ayoubzulfiqar/leetcode)