kiddy

Two sum

leave a comment »

Given an array of integers, find two numbers such that they add up to a specific target number.

The function twoSum should return indices of the two numbers such that they add up to the target, where index1 must be less than index2. Please note that your returned answers (both index1 and index2) are not zero-based.

You may assume that each input would have exactly one solution.

Input: numbers={2, 7, 11, 15}, target=9
Output: index1=1, index2=2

class Solution {
public:
    vector<int> twoSum(vector<int> &numbers, int target) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        int size = numbers.size();
        vector<int> ret;
        ret.clear();
        
        map<int , int> hash;
        for(int i = 0; i < size; i++){
            int val = target - numbers[i];
            if(hash.find(val) != hash.end()){
                ret.push_back(hash[val]);
                ret.push_back(i+1);
            }else{
                hash[numbers[i]] = i+1;
            }
        }
        return ret;
    }
};
Advertisements

Written by linzhongzl

August 23, 2013 at 12:30 am

Posted in Leetcode

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: