[Leetcode] Trapping Rain Water

雨水捕获算法

最新推荐文章于 2021-11-04 09:56:06 发布

原创最新推荐文章于 2021-11-04 09:56:06 发布 · 558 阅读

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本文介绍了一种用于计算二维高度图中能捕获多少雨水的算法。通过预先计算每个位置左侧和右侧的最大高度，该算法有效地确定了每个位置可以捕获的雨水量。

class Solution {
public:
    int trap(int A[], int n) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        vector<int> height(n);
        
        for (int i = 0; i < n; ++i)
        {
            height.push_back(A[i]);
        }
        
        int maxHeight = 0;
        vector<int> leftArr(height.size());
        
        for (int i = 0; i < height.size(); ++i)
        {
            leftArr[i] = maxHeight;
            if (height[i] > maxHeight)
                maxHeight = height[i];
        }
        
        maxHeight = 0;
        vector<int> rightArr(height.size());
        for (int i = height.size() - 1; i >= 0; --i)
        {
            rightArr[i] = maxHeight;
            if (height[i] > maxHeight)
                maxHeight = height[i];
        }
        
        int water = 0;
        for (int i = 0; i < height.size(); ++i)
        {
            int temp = min(leftArr[i], rightArr[i]) - height[i];
            
            if (temp > 0)
                water += temp;
        }
        
        return water;
    }
};