poj 2536 Gopher II_田鼠 usaco-优快云博客

本文链接：https://blog.youkuaiyun.com/stormdpzh/article/details/7582433

本文介绍了一个关于Gopher II的问题解决方法，通过编程实现了一种匹配算法来计算地洞的数量，确保所有土拨鼠都能安全避险。文章详细展示了算法的具体实现过程，包括初始化、搜索匹配等关键步骤。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

wa了一次，因为输出成能跑掉的gopher了，问的是有危险的。

囧！

/*
 * Author: stormdpzh
 * POJ: 2536 Gopher II
 * Created Time: 2012/5/19 10:21:28
 */
#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
#include <cmath>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <algorithm>
#include <functional>

#define sz(v) ((int)(v).size())
#define rep(i, n) for(int i = 0; i < n; i++)
#define repf(i, a, b) for(int i = a; i <= b; i++)
#define repd(i, a, b) for(int i = a; i >= b; i--)
#define out(n) printf("%d\n", n)
#define wh(n) while(scanf("%d", &n) != EOF)
#define whz(n) while(scanf("%d", &n) != EOF && n != 0)
#define lint long long

using namespace std;

const int MaxN = 105;

int n, m, s, v;
int x[MaxN], y[MaxN];
double placex[MaxN], placey[MaxN], holex[MaxN], holey[MaxN];
bool visited[MaxN];
bool mp[MaxN][MaxN];

double getDis(int i, int j)
{
    return sqrt((placex[i] - holex[j]) * (placex[i] - holex[j]) + 
            (placey[i] - holey[j]) * (placey[i] - holey[j]));
}

void init()
{
    memset(mp, false, sizeof(mp));
    
    rep(i, n)
        scanf("%lf%lf", &placex[i + 1], &placey[i + 1]);
    rep(i, m)
        scanf("%lf%lf", &holex[i + 1], &holey[i + 1]);
    
    repf(i, 1, n) repf(j, 1, m) {
        if(getDis(i, j) / (double)v <= (double)s)
            mp[i][j] = true;
    }
}

bool search(int v)
{
    repf(i, 1, m) {
        if(!visited[i] && mp[v][i]) {
            visited[i] = true;
            if(y[i] == -1 || search(y[i])) {
                y[i] = v;
                x[v] = i;
                return true;
            }
        }
    }
    return false;
}

int gao()
{
    int res = 0;
    memset(x, -1, sizeof(x));
    memset(y, -1, sizeof(y));
    repf(i, 1, n) {
        if(x[i] == -1) {
            memset(visited, false, sizeof(visited));
            if(search(i))
                res++;
        }
    }
    return res;
}

int main()
{
    while(scanf("%d%d%d%d", &n, &m, &s, &v) != EOF) {
        init();
        out(n - gao());
    }
    
    return 0;
}