day 4

Author: sachuverma

Diff for: Leetcode Daily Challenge/February-2021/04. Longest Harmonious Subsequence.cpp

@@ -0,0 +1,52 @@
+/*
+Longest Harmonious Subsequence
+==============================
+
+We define a harmonious array as an array where the difference between its maximum value and its minimum value is exactly 1.
+
+Given an integer array nums, return the length of its longest harmonious subsequence among all its possible subsequences.
+
+A subsequence of array is a sequence that can be derived from the array by deleting some or no elements without changing the order of the remaining elements.
+
+Example 1:
+Input: nums = [1,3,2,2,5,2,3,7]
+Output: 5
+Explanation: The longest harmonious subsequence is [3,2,2,2,3].
+
+Example 2:
+Input: nums = [1,2,3,4]
+Output: 2
+
+Example 3:
+Input: nums = [1,1,1,1]
+Output: 0
+
+Constraints:
+1 <= nums.length <= 2 * 104
+-109 <= nums[i] <= 109
+*/
+
+class Solution
+{
+public:
+  int findLHS(vector<int> &nums)
+  {
+    sort(nums.begin(), nums.end());
+    int ans = 0;
+    int i = 0, j = 0;
+    while (i < nums.size() && j < nums.size())
+    {
+      while (j < nums.size() && (nums[j] == nums[i] || nums[j] == nums[i] + 1))
+        j++;
+      if (i != j && nums[i] == nums[j - 1])
+        i++;
+      else
+      {
+        ans = max(ans, j - i);
+        i++;
+      }
+      j = i;
+    }
+    return ans == 1 ? 0 : ans;
+  }
+};

Diff for: Leetcode Daily Challenge/February-2021/README.MD

@@ -4,4 +4,5 @@
 | :-: | :------------- | :-------: |
 | 1.  | [Number of 1 Bits](https://leetcode.com/explore/challenge/card/february-leetcoding-challenge-2021/584/week-1-february-1st-february-7th/3625/) | [cpp](./01.%20Number%20of%201%20Bits.cpp) |
 | 2.  | []() | [cpp](./02.%20.cpp) |
-| 3.  | [Linked List Cycle](https://leetcode.com/explore/challenge/card/february-leetcoding-challenge-2021/584/week-1-february-1st-february-7th/3627/) | [cpp](./03.%20Linked%20List%20Cycle.cpp) |
+| 3.  | [Linked List Cycle](https://leetcode.com/explore/challenge/card/february-leetcoding-challenge-2021/584/week-1-february-1st-february-7th/3627/) | [cpp](./03.%20Linked%20List%20Cycle.cpp) |
+| 4.  | [Longest Harmonious Subsequence](https://leetcode.com/explore/challenge/card/february-leetcoding-challenge-2021/584/week-1-february-1st-february-7th/3628/) | [cpp](./04.%20Longest%20Harmonious%20Subsequence.cpp) |