POJ 1065 Wooden Sticks Greed,DP

排序后贪心或根据第二关键字找最长下降子序列

#pragma comment(linker, "/STACK:1024000000,1024000000")

#include<cstdio>

#include<cstring>

#include<cstdlib>

#include<algorithm>

#include<iostream>

#include<sstream>

#include<cmath>

#include<climits>

#include<string>

#include<map>

#include<queue>

#include<vector>

#include<stack>

#include<set>

using namespace std;

typedef long long ll;

typedef unsigned long long ull;

typedef pair<int,int> pii;

#define pb(a) push(a)

#define INF 0x1f1f1f1f

#define lson idx<<1,l,mid

#define rson idx<<1|1,mid+1,r

#define PI  3.1415926535898

template<class T> T min(const T& a,const T& b,const T& c) {

    return min(min(a,b),min(a,c));

}

template<class T> T max(const T& a,const T& b,const T& c) {

    return max(max(a,b),max(a,c));

}

void debug() {

#ifdef ONLINE_JUDGE

#else

freopen("in.txt","r",stdin);

    freopen("d:\\out1.txt","w",stdout);

#endif

}

int getch() {

    int ch;

    while((ch=getchar())!=EOF) {

        if(ch!=‘ ‘&&ch!=‘\n‘)return ch;

    }

    return EOF;

}
const int maxn=5005;

struct node

{

    int l,w;

    bool operator < (const node &ant) const

    {

        return l<ant.l||l==ant.l&&w<ant.w;

    }

};

node da[maxn];

int vis[maxn];

int main()

{

    int t;

    scanf("%d", &t);

    for(int ca = 1; ca <= t; ca++)

    {

        int n;

        scanf("%d", &n);

        for(int i = 0; i < n; i++)

            scanf("%d%d", &da[i].l, &da[i].w);

        sort(da, da + n);

        memset(vis,0,sizeof(vis));

        int res=0;

        for(int cnt=0;;)

        {

            res++;

            int curl=-1,curw=-1;

            for(int i=0;i<n;i++)

            {

                if(!vis[i]&&da[i].l>=curl&&da[i].w>=curw)

                {

                    vis[i] = 1; cnt++;

                    curl=da[i].l;curw=da[i].w;

                }

            }

            if(cnt==n)break;

        }

        printf("%d\n",res);

    }

    return 0;

}

POJ 1065 Wooden Sticks Greed,DP