Merge pull request #3569 from bansalgaurav852/main

create 0028-find-the-index-of-the-first-occurrence-in-a-string.dart

Author: Ykhan799

dart/0002-add-two-numbers.dart

@@ -0,0 +1,41 @@
+/**
+ * Definition for singly-linked list.
+ * class ListNode {
+ *   int val;
+ *   ListNode? next;
+ *   ListNode([this.val = 0, this.next]);
+ * }
+ */
+class Solution {
+  ListNode? addTwoNumbers(ListNode? l1, ListNode? l2) {
+    ListNode ?listnode;
+    int carry = 0;
+    while (l1 != null || l2 != null) {
+        int val = (l1?.val ?? 0) + (l2?.val ?? 0) + carry;
+        l1 = l1?.next;
+        l2 = l2?.next;
+        if (val > 9){
+            val = val - 10;
+            carry = 1;
+        } else {
+            carry = 0;
+        }
+
+      if (listnode != null)
+        listnode = ListNode(val, listnode);
+
+    else
+     listnode = ListNode(val);
+    }
+    if (carry != 0){
+        listnode = ListNode(carry, listnode);
+    }
+    var list;
+    while (listnode != null) {
+        list = ListNode(listnode.val, list);;
+        listnode = listnode?.next;
+    }
+      return list;
+  }
+
+}

dart/0003-longest-substring-without-repeating-characters.dart

@@ -0,0 +1,27 @@
+class Solution {
+  int lengthOfLongestSubstring(String s) {
+    int max = 0;
+    Map<String, int> map = {};
+
+    List<String> list = s.split('');
+    List<String> result = [];
+
+    for (int i = 0; i < list.length; i++) {
+      if (!result.contains(list[i])) {
+        result.add(list[i]);
+      } else {
+        map.putIfAbsent(result.join(), () => result.length);
+        while (result.contains(list[i])) {
+          result.removeAt(0);
+        }
+        result.add(list[i]);
+      }
+    }
+
+    map.putIfAbsent(result.join(), () => result.length);
+    map.forEach((key, value) {
+      max = max > value ? max : value;
+    });
+    return max;
+  }
+}

dart/0004-median-of-two-sorted-arrays.dart

@@ -0,0 +1,13 @@
+class Solution {
+  double findMedianSortedArrays(List<int> nums1, List<int> nums2) {
+      List<int>list = nums1 + nums2;
+    
+      list.sort();
+     int index = list.length ~/ 2;
+     bool isodd = (list.length & 0x01) != 0;
+     if (!isodd) {
+       return (list[index] + list[index - 1]) / 2;
+     }
+   return double.parse(list[index].toString());
+  }
+}

dart/0028-find-the-index-of-the-first-occurrence-in-a-string.dart

@@ -0,0 +1,6 @@
+class Solution {
+  int strStr(String haystack, String needle) {
+    var result = haystack.replaceAll(needle, '0').indexOf('0');
+    return result;
+  }
+}