FAFU 1136 最长递增子序列

http://acm.fafu.edu.cn/problem.php?id=1136 根据dp建边，建边的时候记得判断如果原本数的大小就ok了 好久没在自家OJ上刷了

#include <iostream>
#include<string.h>
#include<cstdio>
#include<queue>
#include<vector>
//称这个机会吧EK 和DINIC都写一遍复习一下;
using namespace std;
int dp[1105],a[1105],n,max_val,NUM;
int map[1105][1105],flow[1105][1105];
int first[1105],next[1000000],v[1000000];
int dist[1105];
void add(int a,int b)
{
    v[NUM]=b;next[NUM]=first[a];first[a]=NUM;NUM++;v[NUM]=a;next[NUM]=first[b];first[b]=NUM;NUM++;
}
void dpw()
{
    max_val=0;
    int i,j;
    for(i=1;i<=n;i++)
    {
        dp[i]=1;
        for(j=1;j<i;j++)
             if(a[j]<=a[i]&&dp[i]<dp[j]+1)
                  dp[i]=dp[j]+1;

		if(dp[i]>max_val)
        max_val=dp[i];
    }
}
void build()
{
    int i,j;
    for(i=1;i<=n;i++)
    {
        add(i,i+n+1);
		map[i][i+n+1]=1;
        if(dp[i]==1)
        {
               map[0][i]=1;
               add(0,i);
		}
        if(dp[i]==max_val)
        {
            map[i+n+1][n+1]=1;
            add(i+n+1,n+1);

        }else
		{
           for(j=i+1;j<=n;j++)
              if(dp[j]==dp[i]+1&&a[i]<=a[j])
			  {
                add(i+1+n,j);
				map[i+n+1][j]=1;
			  }
		}
    }
}
bool BFS()
{
    memset(dist,-1,sizeof(dist));
    queue<int>q;
    q.push(0);
    int i,x,vv;
    dist[0]=0;
    while(!q.empty())
    {
        x=q.front();
        q.pop();
        for(i=first[x];i!=-1;i=next[i])
        {
            vv=v[i];
            if(dist[vv]==-1&&map[x][vv]>flow[x][vv])
            {
             dist[vv]=dist[x]+1;
             q.push(vv);
            }
        }
    }
    if(dist[n+1]==-1)return false;
     return true;
}
int min_val(int a,int b){return a>b?b:a;}
int find(int x,int low)
{
    int i,a=0,vv;
    if(x==n+1)return low;
    for(i=first[x];i!=-1;i=next[i])
    {
       vv=v[i];
        if(map[x][vv]>flow[x][vv]&&(dist[x]+1==dist[vv])&&(a=find(vv,min_val(low,map[x][vv]-flow[x][vv]))))
       {
         flow[x][vv]+=a;
         flow[vv][x]-=a;
         return a;
        }
    }
    return 0;
}
int main()
{
    int i,temp,ans1,ans2;

	while(scanf("%d",&n)==1){

		 for(i=1;i<=n;i++)
        scanf("%d",&a[i]);
		 if(n==1){
        printf("1\n1\n1\n");

		   }else {
		   NUM=0;
        memset(first,-1,sizeof(first));
        memset(map,0,sizeof(map));
        memset(flow,0,sizeof(flow));

        dpw();
        build();
        ans1=ans2=0;
        while(BFS())
        {
            while((temp=find(0,1<<30)))ans1=ans1+temp;
        }
        map[0][1]=10000000;
        map[1][n+1+1]=10000000;
        map[n][n+1+n]=10000000;
        if(map[n+1+n][n+1]) map[n+1+n][n+1]=10000000;
       memset(flow,0,sizeof(flow));
      while(BFS())
        {
            while((temp=find(0,1<<30)))ans2=ans2+temp;
        }
	   printf("%d\n%d\n%d\n",max_val,ans1,ans2);
		   }
	}
    return 0;
}