leetcode 42 接雨水 C语言实现

题目

代码

按列来看，每次计算当前列可存储水量

int max(int a, int b) {
    return a >= b ? a : b;
}
int min(int a, int b) {
    return a <= b ? a : b;
}
//按列来计算，每次计算当前列可以存储多少水
int trap(int* height, int heightSize){
    if (heightSize == 0 || heightSize == 1) return 0;
    int max_left[heightSize], max_right[heightSize];
    max_left[1] = height[0];
    for (int i = 2; i < heightSize; i++) {
        max_left[i] = max(max_left[i - 1], height[i - 1]);
    }
    max_right[heightSize - 2] = height[heightSize - 1];
    for (int i = heightSize - 3; i >= 0; i--) {
        max_right[i] = max(max_right[i + 1], height[i + 1]);
    }
    int sum = 0;
    for (int i = 1; i < heightSize - 1; i++) {
        int temp = min(max_left[i], max_right[i]);
        if (temp > height[i]) {
            sum += temp - height[i];
        }
    }
    return sum;
}