# 1. Two Sum

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, and you may not use the same element twice.

Example:

Given nums = [2, 7, 11, 15], target = 9,

Because nums[0] + nums[1] = 2 + 7 = 9,
return [0, 1].
class Solution {
public:
vector<int> twoSum(vector<int>& nums, int target) {
int size = nums.size();
vector<int> result;
map<int, int> lookup;
for(int i = 0; i < size; i++) {
int value = target - nums[i];
if (lookup.count(value)) {
result.push_back(lookup[value]);
result.push_back(i);
return result;
} else {
lookup.insert(pair<int, int>(nums[i], i));
}
}
}
};

class Solution(object):
def twoSum(self, nums, target):
"""
:type nums: List[int]
:type target: int
:rtype: List[int]
"""
map = {}
res = []
for i in range(nums.__len__()):
map[target - nums[i]] = i
for i in range(nums.__len__()):
if (map.get(nums[i]) and (map.get(nums[i]) != i)):
res.append(i)
res.append(map.get(nums[i]))
return res


posted @ 2017-11-07 14:13  琴断影花  阅读(104)  评论(0编辑  收藏  举报