Merge pull request #36 from Acejoy/main

Added the Solution To 	Check whether a String is Palindrome or not, Find the triplet that sum to a given value, Find median in a row wise sorted matrix

Array/27.cpp

@@ -0,0 +1,66 @@
+// Problem link : https://practice.geeksforgeeks.org/problems/triplet-sum-in-array-1587115621/1
+
+#include <bits/stdc++.h>
+using namespace std;
+
+
+ // } Driver Code Ends
+
+
+class Solution{
+    public:
+    // function to find the triplet which sum to x
+    // arr[] : The input Array
+    // N : Size of the Array
+    // X : Sum which you need to search for 
+
+    bool find3Numbers(int arr[], int N, int X)
+    {
+        //Your Code Here
+
+        int Sum = 0;
+        sort(arr, arr+N);
+        //printArray(arr);
+
+        for(int i=0; i<N-2; i++){
+
+        	int leftPtr = i+1;
+        	int rightPtr = N-1;
+
+            while(leftPtr<rightPtr) {
+
+                Sum = arr[rightPtr] + arr[leftPtr] +arr[i];
+                //printf("leftptr:%d ,rightptr:%d, partial sum:%d\n",leftPtr, rightPtr, Sum);
+                if(Sum == X) {
+                    return true;
+                } else if( Sum > X) {
+                	rightPtr--;
+                } else {
+                	leftPtr++;
+                }          
+            }
+        }
+
+        return false;
+    }
+
+};
+
+// n = 5, X = 10
+// arr[] = [1 2 4 3 6]
+// Output:
+// 1
+// Explanation:
+// The triplet {1, 3, 6} in 
+// the array sums up to 10.
+
+int main()
+{
+    int N=5,sum=10;
+    int i,A[N] = {1,2,4,3,6};
+
+    Solution ob;
+    cout <<  ob.find3Numbers(A, N, sum) << endl;  
+
+    return 0;
+}

Matrix/2.cpp

@@ -0,0 +1,64 @@
+// { Driver Code Starts
+//Initial template for C++
+
+#include <bits/stdc++.h>
+using namespace std;
+
+
+class Solution{   
+public:
+    int median(vector<vector<int>> &matrix, int r, int c){
+        // code here
+        int minElement = INT_MAX;
+    	int maxELement = INT_MIN;
+
+    	for(int i=0; i<r; i++) {
+    		minElement = min(minElement, matrix[i][0]);
+    		maxELement = max(maxELement, matrix[i][c-1]);
+    	}
+
+    	int desiredElements = (r*c+1)/2;	
+
+    	while(minElement < maxELement) {
+
+    		int currentElements = 0;
+    		int mid = minElement + (maxELement- minElement)/2;
+
+    		for(int i=0; i<r; i++) {
+    			currentElements += upper_bound(matrix[i].begin(), matrix[i].end(), mid) - matrix[i].begin();
+    		}
+
+    		if(currentElements< desiredElements) {
+    			minElement = mid+1;
+    		} else {
+    			maxELement = mid;
+    		}
+    	}
+
+    	return minElement;
+    }
+};
+
+// Input:
+// R = 3, C = 3
+// M = [[1, 3, 5], 
+//      [2, 6, 9], 
+//      [3, 6, 9]]
+
+// Output: 5
+
+// Explanation:
+// Sorting matrix elements gives us 
+// {1,2,3,3,5,6,6,9,9}. Hence, 5 is median. 
+
+int main()
+{
+        int r=3, c=3;
+        vector<vector<int>> matrix(r, vector<int>(c));
+        matrix[0] = {1,3,5};
+        matrix[1] = {2,6,9};
+        matrix[2] = {3,6,9};
+        Solution obj;
+        cout<<obj.median(matrix, r, c)<<endl;        
+    return 0;
+}

String/1.cpp

@@ -0,0 +1,46 @@
+// Problem link : https://practice.geeksforgeeks.org/problems/palindrome-string0817/1
+
+#include<bits/stdc++.h>
+using namespace std;
+
+class Solution{
+public:	
+
+
+	int isPalindrome(string S)
+	{
+	    // Your code goes here
+	    int isPalin=1;
+
+	    int firstIndex = 0;
+	    int lastIndex = S.length()-1;
+
+	    while(firstIndex<lastIndex){
+	        if(S[firstIndex]!=S[lastIndex]){
+	            isPalin=0;
+	            break;
+	        } else {
+	            firstIndex++;
+	            lastIndex--;
+	        }
+	    }
+
+	    return isPalin;
+	}
+
+};
+
+int main(){
+
+    Solution s;
+
+    string demoString = "abba";
+    int res = s.isPalindrome(demoString);
+    if(res==1){
+        cout<<"String is Palindrome\n";
+    } else {
+        cout<<"String is not Palindrome\n";
+    }
+
+    return 0;
+}