题目描述
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].
代码及注释
class Solution {
public:
vector<int> twoSum(vector<int>& nums, int target) {
unordered_map<int,int> numsmap;
vector<int> result;
for(int i = 0;i<nums.size();++i){
numsmap[nums[i]] = i;
}
for(int i = 0;i<nums.size();i++){
int gap = target - nums[i];
if(numsmap.find(gap) != numsmap.end() && numsmap.find(gap) != i){
result.push_back(i+1);
result.push_back(numsmap[gap] + 1);
break;
}
}
return result;
}
};
