LeetCode：Trapping Rain Water

最新推荐文章于 2024-09-02 03:43:19 发布

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本文介绍了一个经典的算法问题——雨水收集。通过给定的高度数组来计算能够收集多少雨水。使用双指针技巧，从两端向中间逼近，同时维护左右两边的最大高度。

Trapping Rain Water

Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it is able to trap after raining.

For example,
Given [0,1,0,2,1,0,1,3,2,1,2,1], return 6.

代码如下：

public int trap(int[] height) {
    if (height == null || height.length == 0) {
        return 0;
    }
    int left = 0, right = height.length - 1;
    int trap = 0, leftMax = 0, rightMax = 0;
    while (left < right) {
        leftMax = Math.max(leftMax, height[left]);
        rightMax = Math.max(rightMax, height[right]);
        if (height[left] < height[right]) {
            trap += leftMax - height[left++];
        } else {
            trap += rightMax - height[right--];
        }
    }
    return trap;
}