POJ2398【判断点在直线哪一侧+二分查找区间】

题意：同POJ2318

#include<algorithm>
#include<cstdio>
#include<cstdlib>
#include<cstring>
using namespace std;
struct point {int x, y;
};
struct Node {point Low, High;
}line[5010];int Num[5010];
int par[5010];
bool cmp(Node A, Node B) {return A.High.x < B.High.x;
}bool is_right(int x, int y, Node ln) {point P = ln.High;point Q = ln.Low;if (((P.x - x)*(Q.y - y) - (P.y - y)*(Q.x - x)) > 0)return true;elsereturn false;
}void bin_seach(int x, int y, int n) {int left = 1;int right = n;while (left <= right) {int mid = (left + right) / 2;if (is_right(x, y, line[mid])) {left = mid + 1;}else {right = mid - 1;}}par[left]++;}
int main() {int n, m, i, j, x1, x2, y1, y2;while (scanf("%d", &n), n) {memset(par, 0, sizeof(par));memset(Num, 0, sizeof(Num));scanf("%d%d%d%d%d", &m, &x1, &y1, &x2, &y2);for (int i = 1; i <= n; i++) {scanf("%d", &line[i].High.x);line[i].High.y = y1;scanf("%d", &line[i].Low.x);line[i].Low.y = y2;}sort(line + 1, line + 1 + n, cmp);int xx, yy;int t = m;while (m--) {scanf("%d%d", &xx, &yy);bin_seach(xx, yy, n);}for (int i = 1; i <= n + 1; i++) {if (par[i])Num[par[i]]++;}printf("Box\n");for (int i = 1; i <= t; i++) {if (Num[i])printf("%d: %d\n", i, Num[i]);}}return 0;
}