提出 #6368441

---

ソースコード 拡げる

#include <bits/stdc++.h> 
#define inf 4294967295
#define N 500000
#define LL long long
#define pi acos(-1)
#define MO 1000000007

using namespace std; 

LL ans;
int ot[N],ne[N],g[N],e,n,k;
LL fac[N]; 

void add(int x,int y){
	ot[++e]=y,ne[e]=g[x],g[x]=e;
	ot[++e]=x,ne[e]=g[y],g[y]=e;	
}

void dfs(int x,int fa){
	int son = 0;
	for (int p = g[x]; p; p = ne[p]){
		int y = ot[p];
		if (y != fa){
			son++;
			dfs(y,x);
		}
	}
	if (son){
		if (fa == -1){
			if (son <= k - 1) ans = ans * (k-1) % MO * fac[k-son] % MO;
			else ans = 0;
		}	else {
			if (son <= k - 2) ans = ans * fac[k-1-son] % MO;
			else ans = 0;
		}
	}
}

int main(){
	scanf("%d%d",&n,&k);
	fac[k]=fac[k-1]=1;
	fac[k-2]=k-2;
	for (int i = k-3; i >= 1; --i) fac[i] = (fac[i+1] * i) % MO;
	for (int i = 1; i < n; ++i) {
		int x,y;
		scanf("%d%d",&x,&y);
		add(x,y);	
	}
	ans = k;
	dfs(1,-1);
	cout << ans << endl;
	return 0;
}

提出情報

コンパイルエラー

./Main.cpp: In function ‘int main()’:
./Main.cpp:40:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d",&n,&k);
                     ^
./Main.cpp:46:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d",&x,&y);
                      ^

ジャッジ結果