Merge pull request matthewsamuel95#261 from zetef/master

Triplet sum

Author: matthewsamuel95

Math/3Sum/3Sum.cpp

@@ -0,0 +1,33 @@
+#include <iostream>
+#include <algorithm>
+#include <unordered_map>
+
+using namespace std;
+
+bool find_triplet( int arr[], int arr_size, int value ) {
+	unordered_map<int, int> map;
+	
+	for ( int i = 0; i < arr_size; i++ )
+		map[arr[i]] = i;
+		
+	for ( int i = 0; i < arr_size - 1; i++ )
+		for ( int j = i + 1; j < arr_size; j++ ) {
+			int sum = value - ( arr[i] + arr[j] );
+			
+			if ( map.find( sum ) != map.end() )
+				if ( map[sum] != i && map[sum] != j ) {
+					cout << '(' << arr[i] << ", " << arr[j] << ", " << sum << ')' << endl; 
+					return true;
+				}
+		}
+	return false;
+}
+
+int main()
+{
+	int arr[] = { 2, 7, 4, 0, 9, 5, 1, 3 };
+	int arr_size = sizeof( arr ) / sizeof( arr[0] );
+	int value = 10;
+	
+	return find_triplet( arr, arr_size, value );
+}