LeetCode 42. 接雨水

题目链接

42. 接雨水

思路分析

与程序员面试金典 面试题 17.21. 直方图的水量相同。

class Solution {
public:
    int trap(vector<int>& height) {
        std::ios::sync_with_stdio(false);
        if(height.empty()) return 0;
        int n = height.size();
        vector<int> left(n), right(n);
        left[0] = height[0], right[n - 1] = height[n - 1];
        for(int i = 1; i < n; i++)
            left[i] = max(height[i], left[i - 1]);
        for(int i = n - 2; i >= 0; i--)
            right[i] = max(height[i], right[i + 1]);
        int res = 0;
        for(int i = 0; i < n; i++)
            res += min(left[i], right[i]) - height[i];
        return res;
    }
};