POJ 3905 Perfect Election

2-SAT 裸题，搞之

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

const int maxn=+;
int N,M;
char s1[],s2[];

stack<int>S;
vector<int>G[maxn];
vector<int>FG[maxn];
int Belong[maxn];
int flag[maxn];
int Block;

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

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

void dfs1(int now)
{
    flag[now]=;
    for(int i=; 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=; i<FG[now].size(); i++)
        if(!Belong[FG[now][i]])
            dfs2(FG[now][i]);
}

bool judge()
{
    for(int i=; i<*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=; i<N; i++)
        if(Belong[*i]==Belong[*i+])
            return ;
    return ;
}

int main()
{
    while(~scanf("%d%d",&N,&M))
    {
        init();
        for(int i=;i<=M;i++)
        {
            scanf("%s%s",s1,s2);
            int num1=,num2=;
            for(int i=;i<strlen(s1);i++) num1=num1*+s1[i]-'';
            for(int i=;i<strlen(s2);i++) num2=num2*+s2[i]-'';

            num1--;num2--;

            if(s1[]=='+'&&s2[]=='+')
            {
                addEgde(*num1,*num2+);
                addEgde(*num2,*num1+);
            }
            if(s1[]=='-'&&s2[]=='-')
            {
                addEgde(*num1+,*num2);
                addEgde(*num2+,*num1);
            }
            if(s1[]=='+'&&s2[]=='-')
            {
                addEgde(*num1,*num2);
                addEgde(*num2+,*num1+);
            }
            if(s1[]=='-'&&s2[]=='+')
            {
                addEgde(*num1+,*num2+);
                addEgde(*num2,*num1);
            }
        }
        if(judge()) printf("1\n");
        else printf("0\n");
    }
    return ;
}