oj.uz

Submission #20019

# Submission time Handle Problem Language Result Execution time Memory
20019 2016-02-25T08:39:53 Z emppu 트리 (kriii4_X) C++14
100 / 100
 169 ms 10812 KB 
#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <cstring>
#include <cassert>

#include <algorithm>
#include <vector>
#include <string>
#include <set>
#include <map>
#include <queue>
#include <deque>
#include <list>
#include <bitset>
#include <tuple>

using namespace std;

#define f0(_X,_Y) for(int (_X)=0;(_X)<(_Y);++(_X))
#define f1(_X,_Y) for(int (_X)=1;(_X)<=(_Y);++(_X))
#define ff(_X,_Y,_Z) for(int (_X)=(_Y);(_X)<=(_Z);++(_X))
#define fF(_X,_Y,_Z) for(int (_X)=(_Y);(_X)<(_Z);++(_X))
#define rf0(_X,_Y) for(int _X=(_Y)-1;(_X)>=0;--(_X))
#define rf1(_X,_Y) for(int _X=(_Y);(_X)>0;--(_X))
#define rff(_X,_Y,_Z) for(int _X=(_Y);(_X)>=(_Z);--(_X))
#define rfF(_X,_Y,_Z) for(int _X=(_Y);(_X)>(_Z);--(_X))
#define PRT(_X) std::cout<< #_X ": "<<_X<<std::endl;

#define scan1(_X) scanf("%d",&_X);
#define scan2(_X,_Y) scanf("%d%d",&_X,&_Y);
#define scan3(_X,_Y,_Z) scanf("%d%d%d",&_X,&_Y,&_Z);
#define define1(_1) int _1; scan1(_1)
#define define2(_1,_2) int _1,_2; scan2(_1,_2)
#define define3(_1,_2,_3) int _1,_2,_3; scan3(_1,_2,_3)
#define EXPAND(_1) _1
#define SELECT(_1,_2,_3,_4,NAME,...) NAME
#define scan(...) EXPAND(SELECT(__VA_ARGS__, scan4, scan3, scan2, scan1)(__VA_ARGS__))
#define define(...) EXPAND(SELECT(__VA_ARGS__, define4, define3, define2, define1)(__VA_ARGS__))
#define print(_X) printf("%d\n",_X)
#define PAIR_STRUCT(_T,_X,_Y,...) struct _T{int _X,_Y,##__VA_ARGS__; bool friend operator < (const _T &p, const _T &q){if(p._X!=q._X) return p._X<q._X; return p._Y<q._Y;}}

typedef long long ll;

const int MOD = 1000000007;
ll mul(ll a, ll b){return a*b%MOD;}
ll add(ll a, ll b){return (a+b)%MOD;}

ll inv(ll a, ll b=MOD)
{
	ll s = 0;  ll  old_s = 1;
	ll r = b;  ll  old_r = a;
	while (r!=0)
	{
		ll quotient = old_r / r;
		tie(old_r, r) = make_tuple(r, old_r - quotient * r);
		tie(old_s, s) = make_tuple(s, old_s - quotient * s);
	}
	ll inv = old_s%MOD;
	if(inv<0) inv += MOD;
	return inv;
}

const int N = 200002;
map<int,int> no;
int r[N],sz[N];

int root(int node)
{
	if(r[node]) return r[node]=root(r[node]);
	return node;
}

ll powmod(ll a, ll b)
{
	a %= MOD;
	b %= MOD-1;
	ll p = 1;
	ll sq = a;
	for(int i=1;i<=b;i*=2)
	{
		if(b&i)
		{
			p = mul(p,sq);
		}
		sq = mul(sq,sq);
	}
	return p;
}


int main()
{
	define(n,m);
	int cnt=0;
	bool cycle = false;
	f1(i,m)
	{
		define(s,e);
		if(no.find(s)==no.end()) no[s]=++cnt, s=cnt, sz[cnt]=1; else s=no[s];
		if(no.find(e)==no.end()) no[e]=++cnt, e=cnt, sz[cnt]=1; else e=no[e];
		int r1 = root(s);
		int r2 = root(e);
		if(r1!=r2)
		{
			r[r2]=r1;
			sz[r1]+=sz[r2];
		}
		else
		{
			cycle=true;
			break;
		}
	}
	if(cycle)
	{
		print(0);
		return 0;
	}
	if(m==n-1)
	{
		print(1);
		return 0;
	}

	ll ans=1;
	f1(i,cnt) if(r[i]==0) ans=mul(ans,sz[i]);


	ans = mul(ans,powmod(n,n-m-2));
	printf("%lld\n",ans);
	return 0;
}

Subtask #1
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 3288 KB Output is correct
2 Correct 0 ms 3288 KB Output is correct
3 Correct 0 ms 3288 KB Output is correct
4 Correct 0 ms 3288 KB Output is correct
5 Correct 0 ms 3288 KB Output is correct
6 Correct 0 ms 3288 KB Output is correct
7 Correct 0 ms 3288 KB Output is correct
8 Correct 0 ms 3288 KB Output is correct
9 Correct 0 ms 3288 KB Output is correct
10 Correct 0 ms 3288 KB Output is correct
11 Correct 0 ms 3288 KB Output is correct
12 Correct 0 ms 3288 KB Output is correct
13 Correct 0 ms 3288 KB Output is correct
14 Correct 0 ms 3288 KB Output is correct
15 Correct 0 ms 3288 KB Output is correct
16 Correct 0 ms 3288 KB Output is correct
17 Correct 0 ms 3288 KB Output is correct
18 Correct 0 ms 3288 KB Output is correct
19 Correct 0 ms 3288 KB Output is correct
20 Correct 0 ms 3288 KB Output is correct
21 Correct 0 ms 3288 KB Output is correct
22 Correct 0 ms 3288 KB Output is correct
23 Correct 0 ms 3288 KB Output is correct
24 Correct 0 ms 3288 KB Output is correct
25 Correct 0 ms 3288 KB Output is correct
26 Correct 0 ms 3288 KB Output is correct
27 Correct 0 ms 3288 KB Output is correct
28 Correct 0 ms 3288 KB Output is correct
29 Correct 0 ms 3288 KB Output is correct
30 Correct 0 ms 3288 KB Output is correct

Subtask #2
91.0 / 91.0

# Verdict Execution time Memory Grader output
1 Correct 14 ms 3816 KB Output is correct
2 Correct 31 ms 4476 KB Output is correct
3 Correct 31 ms 4608 KB Output is correct
4 Correct 12 ms 3816 KB Output is correct
5 Correct 20 ms 4212 KB Output is correct
6 Correct 159 ms 10416 KB Output is correct
7 Correct 162 ms 10680 KB Output is correct
8 Correct 29 ms 5004 KB Output is correct
9 Correct 161 ms 10812 KB Output is correct
10 Correct 157 ms 9888 KB Output is correct
11 Correct 154 ms 7644 KB Output is correct
12 Correct 134 ms 7644 KB Output is correct
13 Correct 149 ms 7644 KB Output is correct
14 Correct 139 ms 7644 KB Output is correct
15 Correct 157 ms 7776 KB Output is correct
16 Correct 137 ms 7776 KB Output is correct
17 Correct 143 ms 7776 KB Output is correct
18 Correct 0 ms 3288 KB Output is correct
19 Correct 145 ms 7908 KB Output is correct
20 Correct 140 ms 7908 KB Output is correct
21 Correct 149 ms 7644 KB Output is correct
22 Correct 151 ms 7776 KB Output is correct
23 Correct 155 ms 7908 KB Output is correct
24 Correct 151 ms 7908 KB Output is correct
25 Correct 107 ms 7908 KB Output is correct
26 Correct 102 ms 7908 KB Output is correct
27 Correct 167 ms 9756 KB Output is correct
28 Correct 169 ms 9756 KB Output is correct
29 Correct 142 ms 7908 KB Output is correct
30 Correct 144 ms 7908 KB Output is correct