Submission #4022852

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Source Code Expand

#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cstdlib>
#include <queue>
using namespace std;
#define N 100050
int head[N],to[N<<1],nxt[N<<1],cnt,n,tmp[22],f[N][22],ans;
inline void add(int u,int v) {
	to[++cnt]=v; nxt[cnt]=head[u]; head[u]=cnt;
}
void merge(int *a,int *b) {
	int i;
	for(i=0;i<=20;i++) a[i]+=b[i];
}
void dfs(int x,int y) {
	int i;
	for(i=head[x];i;i=nxt[i]) if(to[i]!=y) dfs(to[i],x);
	memset(tmp,0,sizeof(tmp));
	for(i=head[x];i;i=nxt[i]) if(to[i]!=y) merge(tmp,f[to[i]]);
	int k=0;
	for(i=20;i>=0;i--) {
		if(tmp[i]>1) {
			k=i+1; break;
		}
	}
	for(;tmp[k];k++) ;
	memcpy(f[x]+k,tmp+k,sizeof(int)*(20-k));
	f[x][k]++;
	ans=max(ans,k);
}
int main() {
	scanf("%d",&n);
	int i,x,y;
	for(i=1;i<n;i++) scanf("%d%d",&x,&y),add(x,y),add(y,x);
	dfs(1,0); printf("%d\n",ans);
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:33:16: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
                ^
./Main.cpp:35:56: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  for(i=1;i<n;i++) scanf("%d%d",&x,&y),add(x,y),add(y,x);
                                                        ^

Judge Result