leetcode

Author: ayoubzulfiqar

Diff for: MiddleOfTheLinkedList/middle_of_the_linked_list.dart

@@ -0,0 +1,92 @@
+/*
+
+
+
+-* 876. Middle of the Linked List *-
+
+
+Given the head of a singly linked list, return the middle node of the linked list.
+
+If there are two middle nodes, return the second middle node.
+
+ 
+
+Example 1:
+
+
+Input: head = [1,2,3,4,5]
+Output: [3,4,5]
+Explanation: The middle node of the list is node 3.
+Example 2:
+
+
+Input: head = [1,2,3,4,5,6]
+Output: [4,5,6]
+Explanation: Since the list has two middle nodes with values 3 and 4, we return the second one.
+ 
+
+Constraints:
+
+The number of nodes in the list is in the range [1, 100].
+
+*/
+
+// Definition for singly-linked list.
+class ListNode {
+  int val;
+  ListNode? next;
+  ListNode([this.val = 0, this.next]);
+}
+
+class A {
+  ListNode? middleNode(ListNode? head) {
+    int n = 0;
+    ListNode? temp = head;
+
+    while (temp!.next != null) {
+      temp = temp.next;
+      n++;
+    }
+
+    int mid = (n % 2 == 0) ? (n ~/ 2) : (n ~/ 2 + 1);
+
+    ListNode? node = head;
+    int i = 0;
+    while (i < mid) {
+      node = node?.next;
+      i++;
+    }
+
+    return node;
+  }
+}
+
+class B {
+  ListNode? middleNode(ListNode? head) {
+    ListNode? slow = head;
+    ListNode? fast = head;
+
+    while (fast != null && fast.next != null) {
+      slow = slow!.next;
+      fast = fast.next!.next;
+    }
+
+    return slow;
+  }
+}
+
+class C {
+  ListNode? middleNode(ListNode? head) {
+    int n = 0;
+    ListNode? current = head;
+    while (current != null) {
+      n++;
+      current = current.next;
+    }
+    current = head;
+    for (int i = 0; i < n / 2; i++) {
+      current = current?.next;
+    }
+    return current;
+  }
+}

Diff for: MiddleOfTheLinkedList/middle_of_the_linked_list.go

@@ -0,0 +1,58 @@
+package main
+
+// Definition for singly-linked list.
+type ListNode struct {
+	Val  int
+	Next *ListNode
+}
+
+func middleNode(head *ListNode) *ListNode {
+	var N int = 0
+	var Temp *ListNode = head
+
+	for Temp.Next != nil {
+		Temp = Temp.Next
+		N++
+	}
+	var mid int
+	if N%2 == 0 {
+		mid = N / 2
+	} else {
+		mid = N/2 + 1
+	}
+	var node *ListNode = head
+	var i int = 0
+	for i < mid {
+		node = node.Next
+		i++
+	}
+	return node
+}
+
+// ===== 2
+
+// func middleNode(head *ListNode) *ListNode {
+// 	var slow *ListNode = head
+// 	var fast *ListNode = head
+// 	for fast != nil && fast.Next != nil {
+// 		slow = slow.Next
+// 		fast = fast.Next.Next
+// 	}
+// 	return slow
+// }
+
+// ========== 3
+
+// func middleNode(head *ListNode) *ListNode {
+// 	var n int = 0
+// 	var current *ListNode = head
+// 	for current != nil {
+// 		n++
+// 		current = current.Next
+// 	}
+// 	current = head
+// 	for i := 0; i < n/2; i++ {
+// 		current = current.Next
+// 	}
+// 	return current
+// }

Diff for: MiddleOfTheLinkedList/middle_of_the_linked_list.md

@@ -0,0 +1,77 @@
+# 🔥 Middle of the Linked List 🔥 || 3 Approaches || Simple Fast and Easy || with Explanation
+
+## Definition for singly-linked list
+
+```dart
+class ListNode {
+  int val;
+  ListNode? next;
+  ListNode([this.val = 0, this.next]);
+}
+```
+
+## Solution - 1
+
+```dart
+class Solution {
+  ListNode? middleNode(ListNode? head) {
+    int n = 0;
+    ListNode? temp = head;
+
+    while (temp!.next != null) {
+      temp = temp.next;
+      n++;
+    }
+
+    int mid = (n % 2 == 0) ? (n ~/ 2) : (n ~/ 2 + 1);
+
+    ListNode? node = head;
+    int i = 0;
+    while (i < mid) {
+      node = node?.next;
+      i++;
+    }
+
+    return node;
+  }
+}
+```
+
+## Solution - 2 Two Pointers
+
+```dart
+class Solution {
+  ListNode? middleNode(ListNode? head) {
+    ListNode? slow = head;
+    ListNode? fast = head;
+
+    while (fast != null && fast.next != null) {
+      slow = slow!.next;
+      fast = fast.next!.next;
+    }
+
+    return slow;
+  }
+}
+```
+
+## Solution - 3 Brute Force
+
+```dart
+
+class Solution {
+  ListNode? middleNode(ListNode? head) {
+    int n = 0;
+    ListNode? current = head;
+    while (current != null) {
+      n++;
+      current = current.next;
+    }
+    current = head;
+    for (int i = 0; i < n / 2; i++) {
+      current = current?.next;
+    }
+    return current;
+  }
+}
+```

Diff for: README.md

@@ -158,6 +158,7 @@ This repo contain leetcode solution using DART and GO programming language. Most
 - [**401.** Binary Watch](BinaryWatch/binary_watch.dart)
 - [**451.** Sort Characters By Frequency](SortCharactersByFrequency/sort_characters_by_frequency.dart)
 - [**2256.** Minimum Average Difference](MinimumAverageDifference/minimum_average_difference.dart)
+- [**876.** Middle of the Linked List](MiddleOfTheLinkedList/middle_of_the_linked_list.dart)
 
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