Added few more problems

Author: Mehulcoder

Language-Tools/Duplicateinarray.cpp

@@ -0,0 +1,66 @@
+/*
+
+				Name: Mehul Chaturvedi
+				IIT-Guwahati
+
+*/
+
+/*
+				PROBLEM STATEMENT
+Given an array of integers of size n which contains numbers from 0 to n - 2. Each number is present at least once. That is, if n = 5, numbers from 0 to 3 is present in the given array at least once and one number is present twice. You need to find and return that duplicate number present in the array.
+Assume, duplicate number is always present in the array.
+Input format :
+Line 1 : Size of input array
+Line 2 : Array elements (separated by space)
+Output Format :
+Duplicate element
+
+*/
+
+
+#include <bits/stdc++.h>
+
+using namespace std;
+int MissingNumber(int arr[], int size){
+    unordered_map<int, int> m1;
+    for (int i = 0; i < size; ++i)
+    {
+    	m1[arr[i]]++;
+    }
+
+    for (int i = 0; i < size; ++i)
+    {
+    	if (m1[arr[i]] == 2)
+    	{
+    		return arr[i];
+    	}
+    }
+
+    return -1;
+}
+
+
+int main( int argc , char ** argv )
+{
+	ios_base::sync_with_stdio(false) ; 
+	cin.tie(NULL) ; 
+	int size;
+	cin >> size;
+	int *input = new int[1 + size];
+	
+	for(int i = 0; i < size; i++)
+		cin >> input[i];
+	
+	cout << MissingNumber(input, size);	
+	
+	delete [] input;
+
+	return 0;
+
+
+
+	return 0 ; 
+
+
+
+}

Language-Tools/a.out

@@ -1,2 +1,2 @@
-7
-2 3 1 6 3 6 2
+9
+0 7 2 5 4 7 1 3 6