Zoj 3656 bit magic (and query set)

Reprinted please indicate the source, thank you http://blog.csdn.net/acm_cxlove/article/details/7854526
By --- cxlove

Leave the question blank

Http://acm.zju.edu.cn/onlinejudge/showProblem.do? Problemcode = 3656.

In fact, the method of querying a set is similar to that of 2-sat.

It is also considered by bit, split into two points.

If a certain number is determined, for example, or 0, both are 0, then the two and 0 sets are merged. If they are 1, they are merged with 1 sets.

If they are exclusive or, the two are the same or different, then the corresponding merge or cross merge

Take a look at other people's ideas. It seems that some of the bit operations on the platform have a wrong priority, and the data is weak.

It's been a long time since we got stuck. The data is illegal.

#include<iostream>#include<cstdio>#include<map>#include<cstring>#include<cmath>#include<vector>#include<algorithm>#include<set>#include<string>#include<queue>#define inf 1<<30#define M 60005#define N 605#define maxn 300005#define eps 1e-10#define zero(a) fabs(a)<eps#define Min(a,b) ((a)<(b)?(a):(b))#define Max(a,b) ((a)>(b)?(a):(b))#define pb(a) push_back(a)#define mp(a,b) make_pair(a,b)#define mem(a,b) memset(a,b,sizeof(a))#define LL long long#define lson step<<1#define rson step<<1|1#define MOD 1000000009#define sqr(a) ((a)*(a))using namespace std;int pre[64*510];int b[505][505],n;void Init(){    for(int i=0;i<n;i++)    {        for(int j=0;j<n;j++)        {            scanf("%d",&b[i][j]);        }    }    for(int i=0;i<(n+10)*64;i++) pre[i]=i;}int find(int x){    return pre[x]=(x==pre[x]?x:find(pre[x]));}void Union(int x,int y){    int ra=find(x),rb=find(y);    pre[ra]=pre[rb]=pre[x]=pre[y]=min(ra,rb);}bool slove(){    for(int i=0; i<n; i++)    {        for(int j=i+1; j<n; j++)            if(b[i][j] != b[j][i]) return 0;        if(b[i][i] != 0) return 0;    }    for(int i=0;i<n;i++)    {        for(int j=i+1;j<n;j++)        {            int m=n*32;            if(i%2==1&&j%2==1)            {                for(int k=0;k<32;k++)                {                    if( ((  b[i][j]>>k ) & 1 )==0 )                    {                        int u=(i+1)*32+k,v=(j+1)*32+k;                        if(find(u)==find(1)||find(v)==find(1)||find(u)==find(v+m)) return false;                        Union(u,0);Union(v,0);                        Union(u+m,1);Union(v+m,1);                    }                }            }            else if(i%2==0&&j%2==0)            {                for(int k=0;k<32;k++)                {                    if(((b[i][j]>>k)&1))                    {                        int u=(i+1)*32+k,v=(j+1)*32+k;                        if(find(u)==find(0)||find(v)==find(0)||find(u)==find(v+m)) return false;                        Union(u,1);Union(v,1);                        Union(u+m,0);Union(v+m,0);                    }                }            }            else            {                for(int k=0;k<32;k++)                {                    int u=(i+1)*32+k,v=(j+1)*32+k;                    if(((b[i][j]>>k)&1))                    {                        if(find(u)==find(v)) return false;                        Union(u,v+m);Union(v,u+m);                    }                    else                    {                        if(find(u)==find(v+m)) return false;                        Union(u,v);Union(u+m,v+m);                    }                }            }        }    }    return true;}int main(){    while(scanf("%d",&n)!=EOF)    {        Init();        puts(slove()?"YES":"NO");    }    return 0;}