poj2536

二分图匹配

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#include <iostream>
#include <cstdlib>
#include <cstring>
#include <cstdio>
#include <cmath>
using namespace std;

#define MAXN 105

struct Point
{
    double x, y;
} gopher[MAXN], hole[MAXN];

int uN, vN, v, s;
bool g[MAXN][MAXN];
int xM[MAXN], yM[MAXN];
bool chk[MAXN];
bool SearchPath(int u)
{
    int v;
    for (v = 0; v < vN; v++)
        if (g[u][v] && !chk[v])
        {
            chk[v] = true;
            if (yM[v] == -1 || SearchPath(yM[v]))
            {
                yM[v] = u;
                xM[u] = v;
                return true;
            }
        }
    return false;
}

int MaxMatch()
{
    int u, ret = 0;
    memset(xM, -1, sizeof(xM));
    memset(yM, -1, sizeof(yM));
    for (u = 0; u < uN; u++)
        if (xM[u] = -1)
        {
            memset(chk, false, sizeof(chk));
            if (SearchPath(u))
                ret++;
        }
    return ret;
}

void input()
{
    for (int i = 0; i < uN; i++)
        scanf("%lf%lf", &gopher[i].x, &gopher[i].y);
    for (int i = 0; i < vN; i++)
        scanf("%lf%lf", &hole[i].x, &hole[i].y);
}

void work()
{
    for (int i = 0; i < uN; i++)
        for (int j = 0; j < vN; j++)
            if (sqrt((gopher[i].x - hole[j].x) * (gopher[i].x - hole[j].x) + (gopher[i].y - hole[j].y) * (gopher[i].y - hole[j].y)) <= v * s)
                g[i][j] = true;
            else
                g[i][j] = false;
}

int main()
{
    //freopen("t.txt", "r", stdin);
    while (scanf("%d%d%d%d", &uN, &vN, &s, &v) != EOF)
    {
        input();
        work();
        printf("%d\n", uN - MaxMatch());
    }
    return 0;
}