OJ-Problems-Source/HDOJ/4751_autoAC.cpp

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#pragma comment(linker, "/STACK:1024000000,1024000000")
#include <stdio.h>
#include <string.h>
#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <string>
#include <math.h>
#include <stdlib.h>
#include <time.h>
using namespace std;
const int MAXN = 110;
int color[MAXN];
int head[MAXN];
struct Edge
{
int to,next;
}edge[MAXN*MAXN];
int tot;
void addedge(int u,int v)
{
edge[tot].to = v;
edge[tot].next = head[u];
head[u] = tot++;
}
void init()
{
tot = 0;
memset(head,-1,sizeof(head));
}
bool dfs(int u,int col)
{
color[u] = col;
for(int i = head[u];i != -1;i = edge[i].next)
{
int v = edge[i].to;
if(color[v] != -1)
{
if(color[v]==col)return false;
continue;
}
if(!dfs(v,!col))return false;
}
return true;
}
int g[MAXN][MAXN];
int main()
{
int n;
while(scanf("%d",&n) == 1)
{
memset(g,0,sizeof(g));
int t;
for(int i = 1;i <= n;i++)
{
while(scanf("%d",&t) && t)
{
g[i][t] = 1;
}
}
init();
for(int i = 1;i <= n;i++)
for(int j = i+1;j <= n;j++)
if(g[i][j] == 0 || g[j][i] == 0)
{
addedge(i,j);
addedge(j,i);
}
memset(color,-1,sizeof(color));
bool flag = true;
for(int i = 1;i <= n;i++)
if(color[i] == -1 && dfs(i,0) == false)
{
flag = false;
break;
}
if(flag)printf("YES\n");
else printf("NO\n");
}
return 0;
}