probem:1. Two Sum

Posted 2020-08-07 nosaferyao

 今天先熟悉熟悉， 希望后面能一次就过
 1 #include <vector>
 2 #include <algorithm>
 3 
 4 using namespace std;
 5 
 6 bool mycompare(const pair<int, int>&a, const pair<int, int>& b)
 7 {
 8     return a.first < b.first;
 9 }
10 
11 class Solution {
12 public:
13     vector<int> twoSum(vector<int>& nums, int target) {
14         vector<pair<int, int> > vecPair(nums.size());
15         for (size_t i = 0; i < vecPair.size(); ++i){
16             vecPair[i] = make_pair(nums[i], i);
17         }
18         sort (vecPair.begin(), vecPair.end(), mycompare);
19         vector<int> result;
20         int a = 0;
21         int b = vecPair.size()-1;
22         while (a<b){
23             int sum = vecPair[a].first + vecPair[b].first;
24             if (sum == target){
25                 break;
26             }
27             if (sum < target){
28                 ++ a;
29             }
30             else {
31                 -- b;
32             }
33         }
34         if (a < b){
35             result.push_back(vecPair[a].second);
36             result.push_back(vecPair[b].second);
37         }
38         return result;
39     }
40 };