HDU 5033 Building

 1 #include <iostream>
 2 #include <algorithm>
 3 #include <vector>
 4 #include <map>
 5 #include <cstring>
 6 #include <set>
 7 #include <bitset>
 8 #include <cstdio>
 9 #include <cmath>
10 
11 #define esp 1e-8
12 #pragma comment(linker, "/STACK:102400000,102400000")
13 #define in freopen("solve_in.txt", "r", stdin);
14 #define pf(x) ((x)*(x))
15 #define bug(x) printf("Line %d: >>>>>>\n", (x));
16 #define lson l, m, rt<<1
17 #define rson m+1, r, rt<<1|1
18 #define pb push_back
19 #define mp make_pair
20 #define pi acos(-1.0)
21 
22 typedef unsigned short US;
23 
24 
25 using namespace std;
26 
27 const int maxn = (int)1e5 + 100;
28 int sta[maxn*2];
29 int dblcmp(double x) {
30     if(fabs(x) < esp) return 0;
31     return x > 0 ? 1 : -1;
32 }
33 struct Node {
34     double x, y;
35     int type, id;
36     bool operator < (const Node &o)const {
37         return dblcmp(x-o.x) < 0;
38     }
39 } p[maxn*2];
40 
41 double cal(int x, int y) {
42     return (p[y].y-p[x].y)/(p[y].x-p[x].x);
43 }
44 int l[maxn], r[maxn];
45 double ans[maxn];
46 double x[maxn];
47 
48 int main() {
49 
50     int T;
51     int n, q;
52     for(int t = scanf("%d", &T); t <= T; t++) {
53         printf("Case #%d:\n", t);
54         int top = 0;
55         scanf("%d", &n);
56         int cnt = 0;
57         for(int i = 1; i <= n; i++) {
58             scanf("%lf%lf", &p[cnt].x, &p[cnt].y);
59             p[cnt++].type = 0;
60         }
61         scanf("%d", &q);
62         for(int i = 1; i <= q; i++) {
63             scanf("%lf", &p[cnt].x);
64             p[cnt].y = 0.0;
65             p[cnt].id = i;
66             x[i] = p[cnt].x;
67             p[cnt++].type = 1;
68         }
69         sort(p, p+cnt);
70         top = 0;
71         for(int i = cnt-1; i >= 0; i--) {
72             while(top >= 2 && cal(i, sta[top]) < cal(sta[top], sta[top-1]))
73                 top--;
74            if(p[i].type){
75                 int id = p[i].id;
76                 r[id] = sta[top];
77            }
78             sta[++top] = i;
79         }
80         top = 0;
81         for(int i = 0; i < cnt; i++){
82             while(top >= 2 && cal(i, sta[top]) > cal(sta[top], sta[top-1]))
83                 top--;
84             if(p[i].type){
85                 int id = p[i].id;
86                 l[id] = sta[top];
87             }
88             sta[++top] = i;
89         }
90         for(int i = 1; i <= q; i++){
91             double d1 = sqrt(pf(p[l[i]].y) + pf(p[l[i]].x-x[i]));
92             double d2 = sqrt(pf(p[r[i]].y) + pf(p[r[i]].x-x[i]));
93             double tmp = acos(fabs(p[l[i]].x-x[i])/d1) + acos(fabs(p[r[i]].x-x[i])/d2);
94             tmp = (pi-tmp)/pi*180.0;
95             printf("%.10f\n", tmp);
96         }
97     }
98     return 0;
99 }