-
Notifications
You must be signed in to change notification settings - Fork 1
Expand file tree
/
Copy pathtest19.java
More file actions
47 lines (45 loc) · 1.43 KB
/
test19.java
File metadata and controls
47 lines (45 loc) · 1.43 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
package byteDance;
/**
* Created by lizeyang on 2020/5/13.
* 接雨水:给定 n 个非负整数表示每个宽度为 1 的柱子的高度图，计算按此排列的柱子，下雨之后能接多少雨水。
*/
public class test19 {
public static int test(int[] nums) {
//时间复杂度O(n)
if (nums == null || nums.length <= 1) {
return 0;
}
int area = 0;
int max = nums[0], maxIndex = 0;
//找到最高处和下标
for (int i = 0; i < nums.length; i++) {
if (nums[i] > max) {
max = nums[i];
maxIndex = i;
}
}
//从左边依次走到最高处，如果左边大于右边，可以接雨水
int tmp = nums[0];
for (int i = 1; i < maxIndex; i++) {
if (nums[i] < tmp) {
area += tmp - nums[i];
} else {
tmp = nums[i];
}
}
//从右边依次走到最高处，如果右边大于左边，可以接雨水
tmp = nums[nums.length - 1];
for (int i = nums.length - 2; i > maxIndex; i--) {
if (nums[i] > tmp) {
tmp = nums[i];
} else {
area += tmp - nums[i];
}
}
return area;
}
public static void main(String[] args) {
int[] nums = {0, 1, 0, 2, 1, 0, 1, 3, 2, 1, 2, 1};
System.out.println(test(nums));
}
}