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29 lines
618 B
29 lines
618 B
2 years ago
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package class22;
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// 本题测试链接 : https://leetcode.com/problems/trapping-rain-water/
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public class Code02_TrappingRainWater {
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public static int trap(int[] arr) {
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if (arr == null || arr.length < 2) {
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return 0;
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}
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int N = arr.length;
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int L = 1;
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int leftMax = arr[0];
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int R = N - 2;
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int rightMax = arr[N - 1];
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int water = 0;
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while (L <= R) {
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if (leftMax <= rightMax) {
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water += Math.max(0, leftMax - arr[L]);
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leftMax = Math.max(leftMax, arr[L++]);
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} else {
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water += Math.max(0, rightMax - arr[R]);
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rightMax = Math.max(rightMax, arr[R--]);
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}
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}
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return water;
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}
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}
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