POJ 2318 TOYS (computational geometry)

Cross-product utilization inferred point segments left or right, and then you can 2 minutes

Code:

#include <cstdio> #include <cstring> #include <algorithm>using namespace std;const int N = 5005;int N, m,    x1, y1, x2, y2;struct Point {int x, y;        Point () {}-point (int x, int y) {this->x = x;    This->y = y; }};typedef Point Vector; Vector operator-(vector A, vector B) {return vector (a.x-b.x, a.y-b.y);}    struct Seg {point A, B;        SEG () {} seg (point A, point B) {this->a = A;    This->b = b; }} seg[n];int ans[n];int cross (vector A, vector B) {return a.x * b.y-a.y * b.x;}    void Gao (point p) {int L = 0, r = N;        while (L < r) {int mid = (L + r)/2;        if (Cross (seg[mid].a-p, seg[mid].b-p) < 0) R = Mid;    else L = mid + 1; } ans[l]++;}        int main () {while (~SCANF ("%d", &n) && N) {memset (ans, 0, sizeof (ans));        scanf ("%d%d%d%d%d", &m, &x1, &y1, &x2, &y2);        int x, y; for (int i = 0; i < n; i++) {scanf ("%d%d", &x, &y);        Seg[i] = Seg (Point (X, y1), point (Y, y2));            } for (int i = 0; i < m; i++) {scanf ("%d%d", &x, &y);        Gao (Point (x, y));        } for (int i = 0; I <= N; i++) printf ("%d:%d\n", I, ans[i]);    printf ("\ n"); } return 0;}

POJ 2318 TOYS (computational geometry)