diff --git a/1014. Best Sightseeing Pair b/1014. Best Sightseeing Pair
new file mode 100644
index 0000000..bc90bac
--- /dev/null
+++ b/1014. Best Sightseeing Pair	
@@ -0,0 +1,11 @@
+class Solution {
+    public int maxScoreSightseeingPair(int[] values) {
+        int result =0;
+        int max = values[0];
+        for(int i=1;i<values.length;i++){
+            result = Math.max(result, max+values[i] - i);
+            max = Math.max(max, values[i] + i);
+        }
+        return result;
+    }
+}
diff --git a/1751. Maximum Number of Events That Can Be Attended II b/1751. Maximum Number of Events That Can Be Attended II
new file mode 100644
index 0000000..d099c85
--- /dev/null
+++ b/1751. Maximum Number of Events That Can Be Attended II	
@@ -0,0 +1,51 @@
+class Solution {
+    int[][] dp=null;
+    public int maxValue(int[][] events, int k) {
+        int n = events.length;
+        dp = new int[n][k+1];
+        for(int[] d:dp){
+            Arrays.fill(d,-1);
+        }
+        if(k == 1) {
+            for(int[] event : events) {
+                max = Math.max(event[2], max);
+            }
+            return max;
+        }
+        
+        Arrays.sort(events,(a,b) -> a[0]==b[0]?a[1]-b[1]:a[0]-b[0]);
+
+        return helper(events,0,k,n); //o(N*K) * O(logN)
+    }
+
+    int helper(int[][] events,int pos,int k,int n){
+        if(pos>=n || k==0){
+            return 0;
+        }
+
+        if(dp[pos][k]>-1){
+            return dp[pos][k];
+        }
+        
+        int nextPos = nextEvent(events,pos,n); // O(logN)
+        int select = events[pos][2] + helper(events,nextPos,k-1,n); 
+        int reject = helper(events,pos+1,k,n);
+        dp[pos][k]= Math.max(select,reject);
+        return dp[pos][k];
+    }
+
+    int nextEvent(int[][] events,int pos, int n){
+        int endDay = events[pos][1];
+        pos++;
+        while(pos<n){
+            int mid = pos + (n-pos)/2;
+            if(events[mid][0]>endDay){
+                n =mid;
+            }
+            else{
+                pos = mid+1;
+            }
+        }
+        return n;
+    }
+}
diff --git a/2116. Check if a Parentheses String Can Be Valid b/2116. Check if a Parentheses String Can Be Valid
new file mode 100644
index 0000000..4875d5f
--- /dev/null
+++ b/2116. Check if a Parentheses String Can Be Valid	
@@ -0,0 +1,36 @@
+class Solution {
+    public boolean canBeValid(String s, String locked) {
+        if(s.length()%2!=0) return false;
+        Stack<Integer> unlocked = new Stack<>();
+        Stack<Integer> open = new Stack<>();
+        char[] stArray = s.toCharArray();
+        char[] lArray = locked.toCharArray();
+
+        for(int i=0;i<lArray.length;i++){
+            if(lArray[i]=='0'){
+                unlocked.push(i);
+            }
+            else if(stArray[i]=='('){
+                open.push(i);
+            }
+            else{
+                if(open.size()>0){
+                    open.pop();
+                }
+                else if(unlocked.size()>0){
+                    unlocked.pop();
+                }
+                else{
+                    return false;
+                }
+            }
+        }
+
+        while(open.size()>0 && unlocked.size()>0 && open.peek()<unlocked.peek()){
+            open.pop();
+            unlocked.pop();
+        }
+        
+        return open.size()==0;
+    }
+}
diff --git a/2958. Length Of Longest Subarray with at most K Frequency b/2958. Length Of Longest Subarray with at most K Frequency
new file mode 100644
index 0000000..4252307
--- /dev/null
+++ b/2958. Length Of Longest Subarray with at most K Frequency	
@@ -0,0 +1,32 @@
+//Time Complexity - O(N)
+//Space Complexity : O(N)
+
+class Solution {
+    public int maxSubarrayLength(int[] nums, int k) {
+        int start = 0, end = 0, result = 1;
+        Map<Integer, Integer> freq = new HashMap<>();
+
+        while(end < nums.length) {
+            int currentFreq = freq.getOrDefault(nums[end], 0);
+
+            if(currentFreq < k) {
+                freq.put(nums[end], currentFreq+1);
+            }
+            else {
+                while(nums[start] != nums[end]) {
+                    freq.put(nums[start], freq.get(nums[start])-1);
+                    start++;
+                }
+                start++;
+            }
+
+            int newWindowLength = end-start+1;
+            result = Math.max(result, newWindowLength);
+
+            end++;
+
+        }
+
+        return result;
+    }
+}
diff --git a/3223. Minimum Length of String After Operations b/3223. Minimum Length of String After Operations
new file mode 100644
index 0000000..506570d
--- /dev/null
+++ b/3223. Minimum Length of String After Operations	
@@ -0,0 +1,14 @@
+class Solution {
+    public int minimumLength(String s) {
+        char[] ch = s.toCharArray();
+        int[] count = new int[26];
+        for(char c:ch){
+            count[c-'a']++;
+        }
+        int result = 0;
+        for(int ct: count){
+            if(ct>0) result+=(ct%2==0?2:1);
+        }
+        return result;
+    }
+}
diff --git a/724. Find Pivot Index b/724. Find Pivot Index
new file mode 100644
index 0000000..c0bd1e9
--- /dev/null
+++ b/724. Find Pivot Index	
@@ -0,0 +1,17 @@
+class Solution {
+    public int pivotIndex(int[] nums) {
+        int total=0;
+        for(int num:nums){
+            total+=num;
+        }
+
+        int leftSum=0;
+        for(int i=0;i<nums.length;i++){
+            if(2*leftSum + nums[i] == total){
+                return i;
+            }
+            leftSum+=nums[i];
+        }
+        return -1;
+    }
+}
diff --git a/README.md b/README.md
index de043eb..8b4fc08 100644
--- a/README.md
+++ b/README.md
@@ -13,6 +13,7 @@ Number | Name of Problem | Leetcode Link | Video Link | Code
 337 | House Robber III | https://leetcode.com/problems/house-robber-iii/ | https://youtu.be/FRP5l83XoZo | https://github.com/Algorithms-Made-Easy/Leetcode-Challenge/blob/main/337.%20House%20Robber%20III
 403 | Frog jump | https://leetcode.com/problems/frog-jump/ | https://youtu.be/3FYCPlIx3YA | https://github.com/Algorithms-Made-Easy/Leetcode-Challenge/blob/main/403.%20Frog%20Jump
 530 | Minimum Absolute Difference in BST | https://leetcode.com/problems/minimum-absolute-difference-in-bst/description/ | https://youtu.be/uDykjVZ5s4o | https://github.com/Algorithms-Made-Easy/Leetcode-Challenge/blob/main/530.%20Minimum%20Absolute%20Difference%20in%20BST 
+724 | Find Pivot Index | https://leetcode.com/problems/find-pivot-index/description/ | https://youtu.be/HSg9QONpcPw | https://github.com/Algorithms-Made-Easy/Leetcode-Challenge/blob/main/724.%20Find%20Pivot%20Index
 862 | Shortest Subarray with Sum at Least K | https://leetcode.com/problems/shortest-subarray-with-sum-at-least-k/description/ | https://youtu.be/eWbH_j6Lgnk | https://github.com/Algorithms-Made-Easy/Leetcode-Challenge/blob/main/862.%20Shortest%20Subarray%20with%20Sum%20at%20Least%20K
 1071 | Greatest Common Divisor of Strings | https://leetcode.com/problems/greatest-common-divisor-of-strings/description/ | https://youtu.be/41iKYE0n0PQ | https://github.com/Algorithms-Made-Easy/Leetcode-Challenge/blob/main/1071.%20Greatest%20Common%20Divisor%20of%20Strings
 1129 | Shortest Path with Alternating Colors | https://leetcode.com/problems/shortest-path-with-alternating-colors/description/ | https://youtu.be/8FcdSwqR3Js | https://github.com/Algorithms-Made-Easy/Leetcode-Challenge/blob/main/1129.%20Shortest%20Path%20with%20Alternating%20Colors
@@ -23,11 +24,13 @@ Number | Name of Problem | Leetcode Link | Video Link | Code
 1510 | Stone Game IV | https://leetcode.com/problems/stone-game-iv/ | https://youtu.be/Gcg_a3r8FA0 | https://github.com/Algorithms-Made-Easy/Leetcode-Challenge/blob/main/1510.%20Stone%20Game%20IV
 1523 | Count Odd Numbers in an Interval Range | https://leetcode.com/problems/count-odd-numbers-in-an-interval-range/description/ | https://youtu.be/HxI78QECe0c | https://github.com/Algorithms-Made-Easy/Leetcode-Challenge/blob/main/1523.%20Count%20Odd%20Numbers%20in%20an%20Interval%20Range
 1696 | Jump Game VI | https://leetcode.com/problems/jump-game-vi/ | https://youtu.be/LiEcBMK5PQs | https://github.com/Algorithms-Made-Easy/Leetcode-Challenge/blob/main/1696.%20Jump%20Game%20VI
+1751 | Maximum Number of Events That Can Be Attended II | https://leetcode.com/problems/maximum-number-of-events-that-can-be-attended-ii/description/ | https://youtu.be/C3r4OTOmfaI | https://github.com/Algorithms-Made-Easy/Leetcode-Challenge/blob/main/1751.%20Maximum%20Number%20of%20Events%20That%20Can%20Be%20Attended%20II
 1834 | Single-Threaded CPU | https://leetcode.com/problems/single-threaded-cpu/ | https://youtu.be/6104EJTG_T4 | https://github.com/Algorithms-Made-Easy/Leetcode-Challenge/blob/main/1834.%20Single-Threaded%20CPU
 1871 | Jump Game VII | https://leetcode.com/problems/jump-game-vii/ | https://youtu.be/bZxWLuiqHes | https://github.com/Algorithms-Made-Easy/Leetcode-Challenge/blob/main/1871.%20Jump%20Game%20VII
 2328 | Number of Increasing Paths in a Grid | https://leetcode.com/problems/number-of-increasing-paths-in-a-grid/description/ | https://youtu.be/kPAv1t2uBjg | https://github.com/Algorithms-Made-Easy/Leetcode-Challenge/blob/main/2328.%20Number%20of%20Increasing%20Paths%20in%20a%20Grid
 2375 | Construct Smallest Number From DI String | https://leetcode.com/problems/construct-smallest-number-from-di-string/ | https://youtu.be/GEqSg0Otq4Y | https://github.com/Algorithms-Made-Easy/Leetcode-Challenge/blob/main/2375.%20Construct%20Smallest%20Number%20From%20DI%20String
 2531 | Make Number of Distinct Characters Equal | https://leetcode.com/problems/make-number-of-distinct-characters-equal/description/ | https://youtu.be/GwWmlpIEIwc | https://github.com/Algorithms-Made-Easy/Leetcode-Challenge/blob/main/2531.%20Make%20Number%20of%20Distinct%20Characters%20Equal
+2598 | Length Of Longest Subarray with at most K Frequency | https://leetcode.com/problems/length-of-longest-subarray-with-at-most-k-frequency/ | https://youtu.be/GwWmlpIEIwc | https://github.com/Algorithms-Made-Easy/Leetcode-Challenge/blob/main/2598.%20Length%20Of%20Longest%20Subarray%20with%20at%20most%20K%20Frequency
 2657 | Find the Prefix Common Array of Two Arrays | https://leetcode.com/problems/find-the-prefix-common-array-of-two-arrays/description/ | https://youtu.be/m6s9dBCBocQ | https://github.com/Algorithms-Made-Easy/Leetcode-Challenge/blob/main/2657.%20Find%20the%20Prefix%20Common%20Array%20of%20Two%20Arrays
 
 # Leetcode-Challenge