oj.uz

답안 #558429

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
558429 2022-05-07T10:01:05 Z andreast12 캥거루 (CEOI16_kangaroo) C++17
0 / 100
 1 ms 212 KB 
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define fi first
#define se second
#define pb push_back
const int mod=1e9+7, maxn=1e4+5;
int n, s, e;
ll res, memo[100][10][2];

ll dp(int mask, int node, int arah) {
	if(__builtin_popcount(mask)==n) {
		if(node==e) return 1;
		return 0;
	}
	if(memo[mask][node][arah]!=-1) return memo[mask][node][arah];
	ll ans=0;
	if(arah) {
		for(int i=node+1; i<=n; i++) {
			if(((1<<(i-1))&mask)==0) ans=(dp(mask|(1<<(i-1)), i, 1-arah)+ans)%mod;
		}
	} else {
		for(int i=node-1; i>0; i--) {
			if(((1<<(i-1))&mask)==0) ans=(dp(mask|(1<<(i-1)), i, 1-arah)+ans)%mod;
		}
	}
	memo[mask][node][arah]=ans;
	return ans;
}

int main() {
	ios_base::sync_with_stdio(false); cin.tie(NULL);
	cin >> n >> s >> e;
	memset(memo, -1, sizeof(memo));
	res=dp(1<<(s-1), s, 0);
	memset(memo, -1, sizeof(memo));
	res=(res+dp(1<<(s-1), s, 1))%mod;
	cout << res << '\n';
}

Subtask #1
0 / 6.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 212 KB Output is correct
2 Incorrect 0 ms 212 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #2
0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 212 KB Output is correct
2 Incorrect 0 ms 212 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #3
0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 212 KB Output is correct
2 Incorrect 0 ms 212 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #4
0 / 49.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 212 KB Output is correct
2 Incorrect 0 ms 212 KB Output isn't correct
3 Halted 0 ms 0 KB -