oj.uz

답안 #19995

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
19995 2016-02-25T08:14:50 Z gs12117 트리 (kriii4_X) C++
100 / 100
 195 ms 11084 KB 
#include<stdio.h>
#include<map>
long long int n,m;
int mod=1000000007;
long long int ans;
std::map<int,int> mp;
int eg[100100][2];
int cnt;
int uft[200100];
int uftn[200100];
int mpow(int x,int y){
	if(y==0)return 1;
	long long int r=mpow(x,y/2);
	r*=r;
	r%=mod;
	if(y%2==1){
		r*=x;
		r%=mod;
	}
	return r;
}
int uftf(int x){
	if(x==uft[x])return x;
	return uft[x]=uftf(uft[x]);
}
int main(){
	int i,j;
	scanf("%d%d",&n,&m);
	for(i=0;i<m;i++){
		scanf("%d%d",&eg[i][0],&eg[i][1]);
		if(mp[eg[i][0]]==0){
			cnt++;
			mp[eg[i][0]]=cnt;
		}
		eg[i][0]=mp[eg[i][0]];
		if(mp[eg[i][1]]==0){
			cnt++;
			mp[eg[i][1]]=cnt;
		}
		eg[i][1]=mp[eg[i][1]];
	}
	for(i=1;i<=cnt;i++){
		uft[i]=i;
		uftn[i]=1;
	}
	for(i=0;i<m;i++){
		if(uftf(eg[i][0])!=uftf(eg[i][1])){
			uftn[uftf(eg[i][0])]+=uftn[uftf(eg[i][1])];
			uft[uftf(eg[i][1])]=uftf(eg[i][0]);
		}
		else{
			printf("0");
			return 0;
		}
	}
	ans=1;
	for(i=1;i<=cnt;i++){
		if(uftf(i)==i){
			ans*=uftn[i];
			ans%=mod;
		}
	}
	if(m==n-1)ans=1;
	else ans*=mpow(n,n-m-2);
	ans%=mod;
	printf("%lld",ans);
}

Subtask #1
9.0 / 9.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 3560 KB Output is correct
2 Correct 0 ms 3560 KB Output is correct
3 Correct 0 ms 3560 KB Output is correct
4 Correct 0 ms 3560 KB Output is correct
5 Correct 0 ms 3560 KB Output is correct
6 Correct 0 ms 3560 KB Output is correct
7 Correct 0 ms 3560 KB Output is correct
8 Correct 0 ms 3560 KB Output is correct
9 Correct 0 ms 3560 KB Output is correct
10 Correct 0 ms 3560 KB Output is correct
11 Correct 0 ms 3560 KB Output is correct
12 Correct 0 ms 3560 KB Output is correct
13 Correct 0 ms 3560 KB Output is correct
14 Correct 0 ms 3560 KB Output is correct
15 Correct 0 ms 3560 KB Output is correct
16 Correct 0 ms 3560 KB Output is correct
17 Correct 0 ms 3560 KB Output is correct
18 Correct 0 ms 3560 KB Output is correct
19 Correct 0 ms 3560 KB Output is correct
20 Correct 0 ms 3560 KB Output is correct
21 Correct 0 ms 3560 KB Output is correct
22 Correct 0 ms 3560 KB Output is correct
23 Correct 0 ms 3560 KB Output is correct
24 Correct 0 ms 3560 KB Output is correct
25 Correct 0 ms 3560 KB Output is correct
26 Correct 0 ms 3560 KB Output is correct
27 Correct 0 ms 3560 KB Output is correct
28 Correct 0 ms 3560 KB Output is correct
29 Correct 0 ms 3560 KB Output is correct
30 Correct 0 ms 3560 KB Output is correct

Subtask #2
91.0 / 91.0

# 결과 실행 시간 메모리 Grader output
1 Correct 13 ms 4088 KB Output is correct
2 Correct 31 ms 4748 KB Output is correct
3 Correct 38 ms 4880 KB Output is correct
4 Correct 11 ms 4088 KB Output is correct
5 Correct 26 ms 4484 KB Output is correct
6 Correct 181 ms 10688 KB Output is correct
7 Correct 183 ms 10952 KB Output is correct
8 Correct 137 ms 6596 KB Output is correct
9 Correct 188 ms 11084 KB Output is correct
10 Correct 174 ms 10160 KB Output is correct
11 Correct 165 ms 7916 KB Output is correct
12 Correct 142 ms 7916 KB Output is correct
13 Correct 164 ms 7916 KB Output is correct
14 Correct 140 ms 7916 KB Output is correct
15 Correct 151 ms 8048 KB Output is correct
16 Correct 173 ms 8048 KB Output is correct
17 Correct 159 ms 8048 KB Output is correct
18 Correct 0 ms 3560 KB Output is correct
19 Correct 159 ms 8180 KB Output is correct
20 Correct 152 ms 8180 KB Output is correct
21 Correct 146 ms 7916 KB Output is correct
22 Correct 164 ms 8048 KB Output is correct
23 Correct 147 ms 8180 KB Output is correct
24 Correct 148 ms 8180 KB Output is correct
25 Correct 115 ms 8180 KB Output is correct
26 Correct 121 ms 8180 KB Output is correct
27 Correct 185 ms 10028 KB Output is correct
28 Correct 195 ms 10028 KB Output is correct
29 Correct 156 ms 8180 KB Output is correct
30 Correct 150 ms 8180 KB Output is correct