Codeforces Round #284 (Div. 2) - c++编程基础

ed below (A is the point representing the house; B is the point representing the university, different blocks are filled with different colors):

$\$ $\$

带入两点，判断使两点值符号不同直线有多少个，

不要直接判断，long long 不够存

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                     using namespace std; long long sx, sy, ex, ey; int n; int main() { cin >> sx >> sy; cin >> ex >> ey; cin >> n; int ans = 0; while (n--) { long long a, b, c; cin >> a >> b >> c; int f1 = (sx * a + sy * b + c) > 0 ? 1 : 0; int f2 = (ex * a + ey * b + c) > 0 ? 1 : 0; if (f1 != f2) { ans++; } } cout << ans << endl; return 0; }

Codeforces Round #284 (Div. 2)(三)