Added codes for 12 April

GeeksForGeeks/April/12-4-24/GFG.java

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+//{ Driver Code Starts
+// Initial Template for Java
+
+import java.io.*;
+import java.util.*;
+
+class GFG {
+    public static void main(String args[]) throws IOException {
+        BufferedReader read =
+            new BufferedReader(new InputStreamReader(System.in));
+        int t = Integer.parseInt(read.readLine());
+        while (t-- > 0) {
+            int N = Integer.parseInt(read.readLine());
+            long Arr[] = new long[N];
+            String[] S = read.readLine().split(" ");
+            for (int i = 0; i < N; i++) Arr[i] = Long.parseLong(S[i]);
+            Solution ob = new Solution();
+            System.out.println(ob.pairAndSum(N, Arr));
+        }
+    }
+}
+// } Driver Code Ends
+
+
+// User function Template for Java
+
+class Solution 
+{
+    static long pairAndSum(int n, long arr[]) 
+    {
+        // code here
+        long ans = 0;
+        for(int i = 0; i < 32; i++) 
+        {
+            long count = 0;
+
+            for(int j = 0; j < n; j++) 
+                count += (arr[j] >> i) & 1;
+
+            ans += (1L << i) * (count * (count - 1) / 2);
+        }
+
+        return ans;
+    }
+}

GeeksForGeeks/April/12-4-24/README.md

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+Time complexity - O(n)
+Space complexity - O(1)

LeetCode/April/12-4-24/README.md

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+Time complexity - O(n)
+Space complexity - O(1)

LeetCode/April/12-4-24/Solution.java

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+class Solution 
+{
+    public int trap(int[] height) 
+    {
+        if (height.length == 0)
+            return 0;
+
+        int ans = 0;
+        int l = 0;
+        int r = height.length - 1;
+        int maxL = height[l];
+        int maxR = height[r];
+
+        while (l < r)
+        {
+            if (maxL < maxR) 
+            {
+                ans += maxL - height[l];
+                maxL = Math.max(maxL, height[++l]);
+            }
+            else 
+            {
+                ans += maxR - height[r];
+                maxR = Math.max(maxR, height[--r]);
+            }
+        }
+
+        return ans;
+    }
+}