问题 B: 喷水装置（二）(在c++上运行有错误，提交AC了)

 1 #include <stdio.h>
 2 #include <math.h>
 3 
 4 int main(int argc, const char * argv[]) {
 5     int m, n;
 6     int w, h;
 7     float from[10001], to[10001];
 8     scanf("%d", &m);
 9     while (m--) {
10         scanf("%d %d %d", &n, &w, &h);
11         int k = 1;
12         float x, r, t = h * 1.0 / 2, sq;
13         for (int i = 0; i < n; i++) {
14             scanf("%f %f", &x, &r);
15             sq = sqrt(r * r - t * t);
16             if (r > t) {
17                 from[k] = x - sq;
18                 to[k++] = x + sq;
19             }
20         }
21         //排序  首要关键词  from  次要关键词  to
22         for (int i = 1; i < k - 1; i++) {
23             for (int j = i + 1; j < k; j++) {
24                 if (from[i] > from[j] || (from[i] == from[j] && to[i] < to[j])) {
25                     float temp = from[i];
26                     from[i] = from[j];
27                     from[j] = temp;
28                     temp = to[i];
29                     to[i] = to[j];
30                     to[j] = temp;
31                 }
32             }
33         }
34         //判断区间头部是否覆盖
35         if (from[1] > 0) {
36             printf("0\n");
37             continue;
38         }
39         int ans = 1;
40         float flagT = to[1], flag = to[1];
41         from[k] = w;
42         for (int i = 2; i < k; i++) {
43             if (from[i] <= flagT && to[i] > flagT && to[i] > flag) {  //查找相对较大的区间
44                 flag = to[i];
45             }
46             if (from[i + 1] > flagT) {
47                 flagT = flag;
48                 ans++;
49             }
50         }
51         if (flagT < w) {  //判断区间尾部是否覆盖
52             printf("0\n");
53         }
54         else {
55             printf("%d\n", ans);
56         }
57     }
58     return 0;
59 }