提出 #44071804

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ソースコード 拡げる

#include<cstdio>
using namespace std;
int k,u,v,n;
int siz[200005],h[200005];
long long ans;
struct AB{
	int e,n;
}a[400005];
void add(int u,int v){
	a[++k].e=v,a[k].n=h[u],h[u]=k;
}
void dfs(int u,int fa){
	int v,sum1=0; 
	long long sum2=0;
	siz[u]=1;
	for(int i=h[u];i;i=a[i].n){
		v=a[i].e;
		if(v != fa){
			dfs(v,u);
			siz[u]+=siz[v];
		}
	}
	for(int i=h[u];i;i=a[i].n){
		v=a[i].e;
		if(v != fa){
			ans=ans+(long long)sum1*siz[v]*(n-siz[u])+(long long)sum2*siz[v];
			sum2+=(long long)sum1*siz[v];
			sum1+=siz[v];
		}
	}		
}
int main(){
	scanf("%d",&n);
	for(int i=1;i<n;i++){
		scanf("%d%d",&u,&v);
		add(u,v),add(v,u);
	}
	dfs(1,0);
	printf("%lld",ans);
	return 0;
}

提出情報

コンパイルエラー

./Main.cpp: In function ‘int main()’:
./Main.cpp:33:7: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   33 |  scanf("%d",&n);
      |  ~~~~~^~~~~~~~~
./Main.cpp:35:8: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   35 |   scanf("%d%d",&u,&v);
      |   ~~~~~^~~~~~~~~~~~~~

ジャッジ結果