bzoj1077 -- 并查集

看这位大佬的题解就可以了。

http://blog.csdn.net/Fuxey/article/details/50573495

代码：

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
#include<vector>
using namespace std;
#define N 60
int i,j,k,n,m,f[N],g[N][N],x,y,A,B,c[N],Cnt,l[N],r[N],a[N],Ans[3],a1,a2,a3,a4,X,Y,b[N],k1,k2,p[3],M;
bool f1,f2,Flag;
char s[N][N];
inline int Find(int x){return f[x]==x?x:f[x]=Find(f[x]);}
int main(){
    scanf("%d%d%d",&n,&A,&B);M=n;
    for(i=1;i<=n;i++)f[i]=i;
    for(i=1;i<=n;i++){
        scanf("%s",s[i]+1);
        for(j=1;j<=n;j++)
        if(s[i][j]=='=')f[Find(i)]=Find(j);
    }
    for(i=1;i<=n;i++)
    for(j=1;j<=n;j++)
    if(s[i][j]=='+')g[Find(i)][Find(j)]=1,g[Find(j)][Find(i)]=-1;else 
    if(s[i][j]=='-')g[Find(i)][Find(j)]=-1,g[Find(j)][Find(i)]=1;
    for(i=1;i<=n;i++)if(Find(i)==i)c[++Cnt]=i;
    for(n=Cnt,i=1;i<=n;i++){
        f1=f2=0;
        for(j=1;j<=n;j++)
        if(g[c[i]][c[j]]==1)f1=1;else if(g[c[i]][c[j]]==-1)f2=1;
        if(!f1||!f2)continue;
        for(a[c[i]]=2,j=1;j<=n;j++)
        if(g[c[i]][c[j]]==1)a[c[j]]=1;else
        if(g[c[i]][c[j]]==-1)a[c[j]]=3;
    }
    for(i=1;i<=n;i++){
        x=c[i];
        if(a[x])l[x]=r[x]=a[x];else{
            l[x]=1,r[x]=3;
            for(j=1;j<=n;j++)
            if(g[x][c[j]]==1)l[x]=2;else
            if(g[x][c[j]]==-1)r[x]=2;
        }
    }
    X=Find(A);Y=Find(B);
    for(n=M,i=1;i<n;i++)
    if(i!=A&&i!=B){
        x=Find(i);
        for(j=i+1;j<=n;j++)
        if(j!=A&&j!=B){
            memset(p,0,sizeof(p));y=Find(j);
            for(a[1]=l[X];a[1]<=r[X];a[1]++)
            for(a[2]=l[Y];a[2]<=r[Y];a[2]++)
            for(a[3]=l[x];a[3]<=r[x];a[3]++)
            for(a[4]=l[y];a[4]<=r[y];a[4]++){
                b[1]=X;b[2]=Y;b[3]=x;b[4]=y;Flag=0;
                for(k1=1;k1<4;k1++)
                for(k2=k1+1;k2<=4;k2++)
                if(a[k1]!=a[k2]&&b[k1]==b[k2]){Flag=1;k1=4;break;}else
                if(g[b[k1]][b[k2]]==1&&a[k1]<=a[k2]){Flag=1;k1=4;break;}else
                if(g[b[k1]][b[k2]]==-1&&a[k1]>=a[k2]){Flag=1;k1=4;break;}
                if(Flag)continue;
                if(a[1]+a[2]>a[3]+a[4])p[0]=1;else
                if(a[1]+a[2]==a[3]+a[4])p[1]=1;else p[2]=1;
            }
            if(p[0]+p[1]+p[2]==1)for(k1=0;k1<3;k1++)Ans[k1]+=p[k1];
        }
    }
    printf("%d %d %d
",Ans[0],Ans[1],Ans[2]);
    return 0;
}