Merge branch 'master' into Next-Permuation

Leetcode Top Interview Questions/README.md

@@ -21,6 +21,7 @@
 - [Minimum Number Of Operations to Move Balls to Each Box](https://leetcode.com/problems/minimum-number-of-operations-to-move-all-balls-to-each-box/submissions/) - [C++ Solution](./solutions/Minimum%20Number%20Of%20Operations%20To%20Move%20All%20Balls%20To%20Each%20Box.cpp)
 - [Group People By Group Size](//https://leetcode.com/problems/group-the-people-given-the-group-size-they-belong-to/) - [C++ Solution](./solutions/Group%20The%20People%20Given%20By%20Group%20Size.cpp)
 - [Next Permutation](https://leetcode.com/problems/next-permutation/) - [C++ Solution](./solutions/Next%20Permutation.cpp)
+- [Sliding Window Maximum](//https://leetcode.com/problems/sliding-window-maximum/) - [C++ Solution](./solutions/Sliding%20Window%20Maximum.cpp)
 
 ### 2. Strings
 
@@ -89,6 +90,7 @@
 
 ### 1. Array
 
+- [4Sum](https://leetcode.com/problems/4sum/) - [Cpp Solution](./solutions/4Sum.cpp)
 - [3Sum](https://leetcode.com/problems/3sum/) - [Cpp Solution](./solutions/3Sum.cpp)
 - [Set Matrix Zeroes](https://leetcode.com/problems/set-matrix-zeroes/) - [Cpp Solution](./solutions/Set%20Matrix%20Zeroes.cpp)
 - [Group Anagrams](https://leetcode.com/problems/group-anagrams/) - [Cpp Solution](./solutions/Group%20Anagrams.cpp)

Leetcode Top Interview Questions/solutions/4Sum.cpp

@@ -0,0 +1,64 @@
+/*
+Given an array nums of n integers, return an array of all the unique quadruplets [nums[a], nums[b], nums[c], nums[d]] such that:
+
+0 <= a, b, c, d < n
+a, b, c, and d are distinct.
+nums[a] + nums[b] + nums[c] + nums[d] == target
+You may return the answer in any order.
+
+ 
+
+Example 1:
+
+Input: nums = [1,0,-1,0,-2,2], target = 0
+Output: [[-2,-1,1,2],[-2,0,0,2],[-1,0,0,1]]
+Example 2:
+
+Input: nums = [2,2,2,2,2], target = 8
+Output: [[2,2,2,2]]
+ 
+
+Constraints:
+
+1 <= nums.length <= 200
+-109 <= nums[i] <= 109
+-109 <= target <= 109
+*/
+class Solution {
+public:
+    vector<vector<int>> fourSum(vector<int>& nums, int target) {
+        int n = nums.size();
+        vector<vector<int>> result;
+        sort(nums.begin(),nums.end());
+        for(int i=0;i<n;i++)
+        {
+            for(int j=i+1;j<n;j++)
+            {
+                int left = j+1, right = n-1;
+                while(left < right)
+                {
+                    int sum = nums[i] + nums[j] + nums[left] + nums[right];
+                    if(sum == target)
+                    {
+                        result.push_back({nums[i],nums[j],nums[left],nums[right]});
+                        while(left < right-2 && nums[left+1] == nums[left])
+                            left++;
+                        while(left < right-2 && nums[right-1] == nums[right])
+                            right--;
+                        left++;
+                        right--;
+                    }
+                    else if(sum < target)
+                        left++;
+                    else
+                        right--;
+                }
+                while(j < n-1 && nums[j+1] == nums[j])
+                    j++;
+            }
+            while(i < n-1 && nums[i+1] == nums[i])
+                i++;
+        }
+        return result;
+    }
+};

Leetcode Top Interview Questions/solutions/Sliding Window Maximum.cpp

@@ -0,0 +1,19 @@
+class Solution {
+public:
+    vector<int> maxSlidingWindow(vector<int>& nums, int k) {
+     int n = nums.size();
+        if (n == 0 || k == 0) return {};
+
+        vector<int> v(n-k+1);
+        deque<int> d;
+
+        for (int i = 0; i < n; ++i) {
+            while (!d.empty() && d.front() <= i-k) d.pop_front();
+            while (!d.empty() && nums[d.back()] < nums[i]) d.pop_back();
+            d.push_back(i);
+            if (i >= k-1) v[i+1-k] = nums[d.front()];
+        }
+        return v;
+    }
+
+};

Striver Sheet/README.md

@@ -1,5 +1,5 @@
 # STRIVER DSA SHEET
-
+[Takeuforward Website](https://takeuforward.org/)      
 [Sheet Link](https://docs.google.com/document/d/1JLKCaz4n4YtYdQ1bJF1X46BKbxldedb6N1OMiXh9Dmo/edit?usp=sharing)
 
 ### Day 1 (Arrays)