Day 62 - first non repeating int

Author: mandliya

README.md

@@ -6,9 +6,9 @@
 
 | Current Status|     Stats     |
 | :------------: | :----------: |
-| Total Problems | 90 |
-| Current Streak | 61 days |
-| Longest Streak | 61 ( August 17, 2015 - October 16, 2015 ) |
+| Total Problems | 91 |
+| Current Streak | 62 days |
+| Longest Streak | 62 ( August 17, 2015 - October 17, 2015 ) |
 
 </center>
 
@@ -126,6 +126,7 @@ Include contains single header implementation of data structures and some algori
 | Print the contents of matrix in a spiral order | [matrix_spiral_print.cpp](common_ds_problems/matrix_spiral_print.cpp)
 | Given a M x N matrix, rotate it by R rotations anticlockwise, and show the resulting matrix. | [rotate_matrix.cpp](common_ds_problems/rotate_matrix.cpp)|
 | Rotate an array by r elements ( left or right ) | [array_rotation.cpp](common_ds_problems/array_rotation.cpp)
+| Given an array of repeating/non-repeating intergeres, determine the first non-repeating int in this array | [first_non_repeating_int.cpp](common_ds_problems/first_non_repeating_int.cpp)|
 
 ### Math Problems
 | Problem | Solution |

common_ds_problems/first_non_repeating_int.cpp

@@ -0,0 +1,46 @@
+/*
+ * Given an array of integers, determine the first non repeating integer in the array.
+ */
+
+#include<iostream>
+#include<map>
+
+
+int nonRepeating(int *arr, int size){
+	std::map<int, int> m;
+	std::map<int,int>::iterator it;
+	for(int i = 0; i < size; ++i){
+		it = m.find(arr[i]);
+		if( it != m.end()){
+			m[arr[i]] = ++(it->second);
+		}
+		else{
+			m[arr[i]] = 1;
+		}
+	}
+
+	for(int i = 0; i < size; ++i){
+		it = m.find(arr[i]);
+		if( it != m.end()){
+			if(it->second == 1)
+				return arr[i];
+		}
+	}
+	return -1;
+
+}
+
+int main(){
+	int size;
+	int *arr;
+	std::cout<<"Enter size:";
+	std::cin>>size;
+	arr = new int[size];
+	std::cout<<"Enter contents of array:";
+	for(int i = 0; i < size; ++i){
+		std::cin>>arr[i];
+	}
+	std::cout<<"First Non repeating integer in array:"<< nonRepeating(arr,size)<<std::endl;
+	delete[] arr;
+	return 0;
+}