1. Two Sum QuestionEditorial Solution My Submissions

开始刷leetcode了，跟acm那种提交方式还是有一点不同的，需要慢慢习惯

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].

整个题目可以用最简单的暴力，但是就时间慢。

我是用了mutlimap（因为案例有重复），map的特性会自动对key排序，然后从第一个数和最后一个数开始遍历找到答案。

class Solution {
public:
vector<int> twoSum(vector<int>& nums, int target) {
multimap<int, int>a;
vector<int>::iterator v;
int num = 0;
for(v = nums.begin(); v != nums.end(); v++)
{
a.insert(pair<int,int>(nums[num],num));
num++;
}

multimap<int, int>::iterator i1;
multimap<int, int>::iterator i2;
int ii;
for(i2 = a.begin(), ii = 0; ii < num - 1; ++ii, i2++);
vector<int> n;
for(i1 = a.begin(); i1 != i2;)
{
if(i1 -> first + i2->first > target)
i2--;
else if(i1 -> first + i2->first < target)
i1++;
else
{
n.push_back(i1 -> second);
n.push_back(i2 -> second);
break;
}
}
return n;
}
};