70 lines
1.2 KiB
C++
70 lines
1.2 KiB
C++
#include<cstdio>
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#include<cstring>
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#include<vector>
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#include<algorithm>
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using namespace std;
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const int maxn=205;
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struct TwoSAT
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{
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int n,stk[maxn*2],mark[maxn*2],c;
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vector<int> G[maxn*2];
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void init(int nn)
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{
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n=nn;
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for(int i=0;i<n*2;i++) G[i].clear();
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memset(mark,0,sizeof(mark));
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}
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void Add(int x,int xval,int y,int yval)
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{
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// printf("a[%d] equals to %d or a[%d] equals to %d\n",x,xval,y,yval);
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x=x*2+xval; y=y*2+yval;
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G[x^1].push_back(y);
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G[y^1].push_back(x);
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}
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bool dfs(int u)
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{
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if(mark[u^1]) return false;
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if(mark[u]) return true;
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mark[u]=1;
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stk[c++]=u;
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for(int v:G[u]) if(!dfs(v)) return false;
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return true;
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}
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bool solve()
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{
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for(int i=0;i<n*2;i+=2) if(!mark[i]&&!mark[i+1])
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{
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c=0;
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if(!dfs(i))
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{
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while(c>0) mark[stk[--c]]=0;
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if(!dfs(i+1)) return false;
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}
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}
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return true;
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}
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}alg;
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int T,n,m,hsh[128];
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int main()
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{
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#ifdef local
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freopen("pro.in","r",stdin);
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#endif
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scanf("%d",&T);
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hsh['m']=0; hsh['h']=1;
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while(T-->0)
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{
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scanf("%d%d",&n,&m);
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alg.init(n);
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while(m-->0)
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{
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char a[10],b[10]; scanf("%s%s",a,b);
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int x,y; sscanf(a+1,"%d",&x); sscanf(b+1,"%d",&y);
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x--; y--;
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alg.Add(x,hsh[a[0]],y,hsh[b[0]]);
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}
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puts(alg.solve()?"GOOD":"BAD");
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}
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return 0;
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}
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