题目传送门
1 /*
2 水题，就是用三点共线的式子来判断射击次数
3 */
4 #include <cstdio>
5 #include <cmath>
6 #include <string>
7 #include <cstring>
8 #include <iostream>
9 #include <algorithm>
10 #include <map>
11 #include <set>
12 #include <vector>
13 using namespace std;
14
15 const int MAXN = 1e3 + 10;
16 int x[MAXN], y[MAXN];
17 bool used[MAXN];
18
19 int main(void)
20 {
21 //freopen ("B.in", "r", stdin);
22
23 int n, x0, y0;
24
25 while (~scanf ("%d%d%d", &n, &x0, &y0))
26 {
27 memset (used, 0, sizeof (used));
28
29 for (int i=1; i<=n; ++i)
30 {
31 scanf ("%d%d", &x[i], &y[i]);
32 x[i] -= x0; y[i] -= y0;
33 }
34
35 int cnt = 0;
36 for (int i=1; i<=n; ++i)
37 {
38 if (!used[i])
39 {
40 cnt++;
41 for (int j=i; j<=n; ++j)
42 {
43 if (!used[j] && (x[i] * y[j] == x[j] * y[i]))
44 used[j] = 1;
45 }
46 }
47 }
48
49 printf ("%d
", cnt);
50 }
51
52 return 0;
53 }