HDU 4115 Eliminate the Conflict

#include<cstdio>
#include<cstring>
#include<cmath>
#include<stack>
#include<queue>
#include<algorithm>
using namespace std;

const int maxn=60000+10;

int T,N,M;
stack<int>S;
vector<int>G[maxn];
vector<int>FG[maxn];
int Belong[maxn];
int flag[maxn];
int Block;

int X[maxn];

void init()
{
    for(int i=0; i<maxn; i++) G[i].clear();
    for(int i=0; i<maxn; i++) FG[i].clear();
    memset(Belong,0,sizeof Belong);
    memset(flag,0,sizeof flag);
    while(!S.empty()) S.pop();
    Block=0;
}

void addEdge(int x,int y)
{
    G[x].push_back(y);
    FG[y].push_back(x);
}

void dfs1(int now)
{
    flag[now]=1;
    for(int i=0; i<G[now].size(); i++)
        if(!flag[G[now][i]])
            dfs1(G[now][i]);
    S.push(now);
}

void dfs2(int now)
{
    Belong[now]=Block;
    for(int i=0; i<FG[now].size(); i++)
        if(!Belong[FG[now][i]])
            dfs2(FG[now][i]);
}

bool judge()
{
    for(int i=0; i<6*N; i++) if(!flag[i]) dfs1(i);
    while(!S.empty())
    {
        int Top=S.top();
        S.pop();
        if(!Belong[Top])
        {
            Block++;
            dfs2(Top);
        }
    }
    for(int i=0; i<3*N; i++)
        if(Belong[i]==Belong[i+3*N])
            return 0;
    return 1;
}

void read()
{
    int A,B,C;
    for(int i=0;i<N;i++)
    {
        addEdge(3*i+0,3*i+1+3*N);
        addEdge(3*i+0,3*i+2+3*N);

        addEdge(3*i+1,3*i+0+3*N);
        addEdge(3*i+1,3*i+2+3*N);

        addEdge(3*i+2,3*i+0+3*N);
        addEdge(3*i+2,3*i+1+3*N);
    }
    for(int i=0;i<N;i++)
    {
        scanf("%d",&X[i]); X[i]--;
        if(X[i]==0)
        {
            addEdge(3*i+1+3*N,3*i+0);
            addEdge(3*i+0+3*N,3*i+1);
        }
        else if(X[i]==1)
        {
            addEdge(3*i+1+3*N,3*i+2);
            addEdge(3*i+2+3*N,3*i+1);
        }
        else if(X[i]==2)
        {
            addEdge(3*i+0+3*N,3*i+2);
            addEdge(3*i+2+3*N,3*i+0);
        }
    }
    for(int i=1;i<=M;i++)
    {
        scanf("%d%d%d",&A,&B,&C);
        A--,B--;
        if(C==0)
        {
            addEdge(3*A+0,3*B+0);
            addEdge(3*A+1,3*B+1);
            addEdge(3*A+2,3*B+2);

            addEdge(3*B+0,3*A+0);
            addEdge(3*B+1,3*A+1);
            addEdge(3*B+2,3*A+2);
        }

        else if(C==1)
        {
            addEdge(3*A+0,3*B+0+3*N);
            addEdge(3*A+1,3*B+1+3*N);
            addEdge(3*A+2,3*B+2+3*N);

            addEdge(3*B+0,3*A+0+3*N);
            addEdge(3*B+1,3*A+1+3*N);
            addEdge(3*B+2,3*A+2+3*N);
        }
    }
}

int main()
{
    scanf("%d",&T);
    for(int Case=1;Case<=T;Case++)
    {
        scanf("%d%d",&N,&M);
        init();
        read();
        printf("Case #%d: ",Case);
        if(judge()) printf("yes\n");
        else printf("no\n");
    }
    return 0;
}