首先排个序,然后找一次0花费,然后再找一次0花费,然后再找一次0花费,然后再找一次0花费.........

最后看找了几次,+1就是答案

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#include<cstdlib>
#include<vector>
using namespace std;
struct node
{
    int l,w;
    friend istream & operator >>(istream &is,node &a)
    {
        is>>a.l>>a.w;
        return is;
    }
};
bool cmp(node a,node b)
{
    return a.l!=b.l?a.l<b.l:a.w<b.w;
}
bool operator <=(node a,node b)
{
    return a.l<=b.l&&a.w<=b.w;
}
int main()
{
    //freopen("in","r",stdin);
    node box[5010];
    bool vis[5010];
    int ans,i,n,j,T;
    node p;
    cin>>T;
    while(T--)
    {
        cin>>n;
        for(i=0;i<n;i++)
            cin>>box[i];
        ans=1;
        memset(vis,0,sizeof(vis));
        sort(box,box+n,cmp);
        p=box[0];
        for(i=0;i<n;i++)
        {
            if(vis[i])
                continue;
            if(!(p<=box[i]))
                ans++;
            p=box[i];
            for(j=i+1;j<n;j++)
            {
                if(vis[j])
                    continue;
                if(p<=box[j])
                {
                    p=box[j];
                    vis[j]=1;
                }
            }
        }
        cout<<ans<<endl;
    }
    return 0;
}

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