POJ 2912 Rochambeau

#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;
int n, m, fa[1505], pla1[2005], pla2[2005], winn[2005], det[505], cntn, maxn,whic;
char opt;
int myfind(int x){
    return fa[x]==x?x:fa[x]=myfind(fa[x]);
}
int chk(int x){
    for(int i=0; i<3*n; i++)    fa[i] = i;
    for(int i=1; i<=m; i++){
        if(pla1[i]==x || pla2[i]==x)    continue;
        int uu1=myfind(pla1[i]), uu2=myfind(pla1[i]+n), uu3=myfind(pla1[i]+n+n);
        int vv1=myfind(pla2[i]), vv2=myfind(pla2[i]+n), vv3=myfind(pla2[i]+n+n);
        if(winn[i]==1){
            if(uu1==vv1 || uu2==vv1)    return i;
            fa[vv2] = uu1;
            fa[vv3] = uu2;
            fa[vv1] = uu3;
        }
        else if(!winn[i]){
            if(uu1==vv2 || uu2==vv1)    return i;
            fa[vv1] = uu1;
            fa[vv2] = uu2;
            fa[vv3] = uu3;
        }
        else{
            if(uu1==vv1 || uu1==vv2)    return i;
            fa[vv1] = uu2;
            fa[vv2] = uu3;
            fa[vv3] = uu1;
        }
    }
    return 0;
}
int main(){
    while(scanf("%d %d", &n, &m)!=EOF){
        for(int i=1; i<=m; i++){
            scanf("%d%c%d", &pla1[i], &opt, &pla2[i]);
            if(opt==‘=‘)    winn[i] = 0;
            else    winn[i] = opt==‘>‘?1:-1;
        }
        for(int i=0; i<n; i++)  det[i] = chk(i);
        cntn = maxn = 0;
        for(int i=0; i<n; i++){
            if(!det[i]) cntn++, whic=i;
            maxn = max(maxn, det[i]);
        }
        if(!cntn)   printf("Impossible\n");
        else if(cntn>1) printf("Can not determine\n");
        else    printf("Player %d can be determined to be the judge after %d lines\n", whic, maxn);
    }
    return 0;
}