[LeetCode] 3Sum Closest

算法渣，现实基本都参考或者完全拷贝[戴方勤([email protected])]大神的leetcode题解，此处仅作刷题记录。

 

 1 class Solution {

 2 public:

 3     int threeSumClosest(vector<int> &num, int target) {

 4         int result = 0;

 5         int min_gap = INT_MAX;

 6 

 7         sort(num.begin(), num.end()); // 排序

 8 

 9         auto last = num.end();

10         for (auto a = num.begin(); a < prev(last, 2); ++a) {

11             auto b = next(a);

12             auto c = prev(last);

13             while (b < c) {

14                 const int sum = *a + *b + *c;

15                 const int gap = abs(sum - target);

16 

17                 if (gap < min_gap) {

18                     result = sum;

19                     min_gap = gap;

20                 }

21 

22                 if (sum < target)

23                     ++b;

24                 else

25                     --c;

26             }

27         }

28 

29         return result;

30     }

31 };