Submission #1166007

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Source Code Expand

#include <cstdio>
const int M=101000;
#define A(a,b) y[++t]=b,N[t]=F[a],F[a]=t
int n,i,u,v,x,t,y[2*M],N[2*M],F[2*M],Q[2*M];
inline int DFS(int u,int f) {
	int K=0,P=0,S=0;
	for (int j=F[u];j;j=N[j])if(y[j]!=f)S|=((K=DFS(y[j],u))&P),P|=K;
	return(P|((1<<Q[S]+1)-1))+1;
}
int main() {
	scanf("%d",&n);
	for (i=0;i<n-1;i++) scanf("%d%d",&u,&v),A(u,v),A(v,u);
	for (Q[0]=-1,i=2;!(i>>17);i++) Q[i]=Q[i>>1]+1;
	printf("%d\n",Q[DFS(1,0)]);
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:11:16: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
                ^
./Main.cpp:12:55: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  for (i=0;i<n-1;i++) scanf("%d%d",&u,&v),A(u,v),A(v,u);
                                                       ^

Judge Result