poj 2398 Toy Storage

http://poj.org/problem?id=2398

poj2318的升级版，只是中间的n个隔板未排序，输出的是装有i个玩具的区域的个数，其他完全一样

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<queue>
#include<cmath>

using namespace std;

#define N 5110
#define INF 0x3f3f3f3f
#define MOD
#define met(a, b) memset(a, b, sizeof(a))

typedef long long LL;

using namespace std;

struct point
{
    int x, y;
};

struct line
{
    point up, down;
}p[N];

int ans[N];

bool cmp (line a, line b)
{
    return a.down.x < b.down.x;
}

int xmult (point p1, point p2, point p0)
{
    return (p1.x-p0.x) * (p2.y-p0.y) - (p2.x-p0.x) * (p1.y-p0.y);
}///叉积

void Search (point Q, int n)
{
    int l = 1, r = n;

    while (l < r)
    {
        int mid = (l + r) >> 1;

        if (xmult (Q, p[mid].up, p[mid].down) > 0) l = mid+1;
        else r = mid;
    }

    if (xmult (Q, p[l].up, p[l].down) > 0) ans[l+1]++;
    else ans[l]++;
}

int main ()
{
    int n, m, x1, y1, x2, y2;

    while (scanf ("%d", &n), n)
    {
        met (p, 0);
        met (ans, 0);
        scanf ("%d %d %d %d %d", &m, &x1, &y1, &x2, &y2);

        for (int i=1; i<=n; i++)
        {
            int u, l;
            scanf ("%d %d", &u, &l);
            p[i].up = (point) {u, y1};
            p[i].down = (point) {l, y2};
        }

        sort (p+1, p+n+1, cmp);

        point Q;
        for (int i=0; i<m; i++)
        {
            scanf ("%d %d", &Q.x, &Q.y);
            Search (Q, n);
        }

        sort (ans+1, ans+n+2);
        int cnt = 0, sum = 0;

        puts ("Box");

        for (int i=1; i<=n+2; i++)
        {
            if (ans[i] && !cnt)
            {
                cnt = ans[i];
                sum = 0;
            }

            if (ans[i] == cnt && cnt)
                sum++;
            else if (cnt && ans[i] != cnt)
            {
                printf ("%d: %d\n", cnt, sum);
                cnt = ans[i];
                sum = 1;
            }
        }
    }
    return 0;
}