hdu2614 DFS

#include <iostream>#include <cstdio>#include <cmath>#include <algorithm>#include <cstring>#include <queue>using namespace std;int f[20][20],flag[20];int ans;int n;void DFS(int now,int tim,int maxx){    ans=max(ans,maxx);    if(ans==n) return ;    for(int i=1;i<n;i++){        if(f[now][i]>=tim && i!=now){            if(!flag[i]){                flag[i]=1;                DFS(i,f[now][i],maxx+1);                flag[i]=0;            }        }    }}int main(){  //  freopen("in.txt","r",stdin);    while(scanf("%d",&n)!=EOF){        ans=1;        for(int i=0;i<n;i++)            for(int j=0;j<n;j++){                scanf("%d",&f[i][j]);            }        memset(flag,0,sizeof(flag));        flag[0]=1;        DFS(0,0,1);        printf("%d\n",ans);    }    return 0;}