hdu 4160 dolls 最少路径覆盖

最少路径覆盖 == n - 最大匹配

#include<iostream>
#include<vector>
#include<algorithm>
#include<cstdio>
#include<cstring>
#include<string>
#include<iomanip>
#include<cassert>
using namespace std;

const int maxn = 1011;
const int add = 500;

struct zz
{
    int x;
    int y;
    int z;
}zx[maxn];
vector<int>g[maxn];
int link[maxn];
int use[maxn];
int n;

bool dfs(int now)
{
    int to;
    for(int i=0;i<g[now].size();i++)
    {
        to = g[now][i];
        if( !use[to] )
        {
            use[to] = true;
            if(link[to] == -1 || dfs(link[to]) )
            {
                link[to] = now;
                return true;
            }
        }
    }
    return false;
}

int matching()
{
    int ans = 0;
    memset(link,-1,sizeof(link));
    memset(use,false,sizeof(use));
    for(int i=1;i<=n;i++)
    {
        memset(use,false,sizeof(use));
        if(dfs(i))
        {
            ans++;
        }
    }
    return ans;
}

bool can(int i,int j)
{
    if(zx[i].x < zx[j].x && zx[i].y < zx[j].y && zx[i].z < zx[j].z )
    {
        return true;
    }
    return false;
}

int main()
{
    while(cin>>n)
    {
        if(n==0)
        {
            break;
        }
        for(int i=1;i<maxn;i++)
        {
            g[i].clear();
        }
        for(int i=1;i<=n;i++)
        {
            cin>>zx[i].x>>zx[i].y>>zx[i].z;
        }
        int from;
        int to;
        for(int i=1;i<=n;i++)
        {
            for(int j=1;j<=n;j++)
            {
                if(can(i,j))
                {
                    from = i;
                    to = j + add;
                    g[from].push_back(to);
                    g[to].push_back(from);
                }
            }
        }
        cout<< n - matching()<<endl;
    }
    return 0;
}