接雨水（4.4 leetcode每日打卡）

 1 int trap(int* height, int heightSize)
 2 {
 3     int n = heightSize;
 4     if(n == 0)
 5     {
 6         return 0;
 7     }
 8     int maxIndex = 0;
 9     int max = height[0];
10     for(int i = 1; i < n; i++)
11     {
12         if(height[i] > max)
13         {
14             maxIndex = i;
15             max = height[i];
16         }
17     }
18     int res = 0,cur = height[0];
19     for(int i = 1; i < maxIndex; i++)
20     {
21         if(height[i] < cur)
22         {
23             res += cur - height[i];
24         }
25         else
26         {
27             cur = height[i];
28         }
29     }
30     cur = height[n-1];
31     for(int i = n-2; i > maxIndex; i--)
32     {
33         if(height[i] < cur)
34         {
35             res += cur-height[i];
36         }
37         else
38         {
39             cur = height[i];
40         }
41     }
42     return res;
43 }