[LeetCode] 3Sum Closest

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

 

class Solution {
public:
    int threeSumClosest(vector<int> &num, int target) {
        int result = 0;
        int min_gap = INT_MAX;

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

        auto last = num.end();
        for (auto a = num.begin(); a < prev(last, 2); ++a) {
            auto b = next(a);
            auto c = prev(last);
            while (b < c) {
                const int sum = *a + *b + *c;
                const int gap = abs(sum - target);

                if (gap < min_gap) {
                    result = sum;
                    min_gap = gap;
                }

                if (sum < target)
                    ++b;
                else
                    --c;
            }
        }

        return result;
    }
};