Merge pull request #2 from FreeTymeKiyan/Linsen_test

Linsen test

Author: FreeTymeKiyan

C++/001_Two_Sum.cpp

@@ -0,0 +1,71 @@
+/*
+ *Given an array of integers, return indices of the two numbers such that they add up to a specific target.
+ *You may assume that each input would have exactly one solution.
+
+ *Example:
+ *Given nums = [2, 7, 11, 15], target = 9,
+ *Because nums[0] + nums[1] = 2 + 7 = 9,
+ *return [0, 1].
+
+ *UPDATE (2016/2/13):
+ *The return format had been changed to zero-based indices. Please read the above updated description carefully
+
+ *Tag: Array, Hash Table
+ 
+ *Author: Linsen Wu
+*/
+
+#include "stdafx.h"
+#include "iostream"
+#include <vector>
+#include <unordered_map>
+
+using namespace std;
+
+class Solution {
+public:
+    vector<int> twoSum(vector<int> &numbers, int target) {
+		vector<int> indexResults;
+		unordered_map<int, int> index_map;
+		unordered_map<int, int>::iterator it;
+        for (int i=0; i<numbers.size(); ++i) {
+			it = index_map.find(target-numbers[i]);
+			if (it != index_map.end()) {
+				indexResults.push_back(it->second);
+				indexResults.push_back(i);
+				return indexResults;
+			} else {
+				index_map[numbers[i]] = i;
+			}
+		}
+		return indexResults;
+    }
+};
+
+/*
+Save the numbers into an unordered map when searching
+Time:	O(n)
+Space:	O(n)
+*/
+
+int _tmain(int argc, _TCHAR* argv[])
+{
+	vector<int> input, output;
+	input.push_back(-1);
+	input.push_back(7);
+	input.push_back(11);
+	input.push_back(15);
+
+	Solution _solution;
+	output = _solution.twoSum(input, 6);
+
+	for(vector<int>::iterator iterator = output.begin(); iterator != output.end(); iterator++)
+		cout<<((*iterator))<<endl;
+
+	system("Pause");
+
+	return 0;
+}
+
+
+