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Submission #260470

# Submission time Handle Problem Language Result Execution time Memory
260470 2020-08-10T10:46:11 Z shayan_p Ruins 3 (JOI20_ruins3) C++14
100 / 100
 370 ms 14764 KB 
// And you curse yourself for things you never done

#include<bits/stdc++.h>

#define F first
#define S second
#define PB push_back
#define sz(s) int((s).size())
#define bit(n,k) (((n)>>(k))&1)

using namespace std;

typedef long long ll;
typedef pair<int,int> pii;

const int maxn = 1220, mod = 1e9 + 7, inf = 1e9 + 10;

int dp[maxn][maxn], C[maxn][maxn];
bool is[maxn];

int dp2[maxn][maxn], F[maxn];

int main(){
    ios_base::sync_with_stdio(false); cin.tie(0); cout.tie();

    for(int i = 0; i < maxn; i++){
	C[i][i] = C[i][0] = 1;
	for(int j = 1; j < i; j++)
	    C[i][j] = (C[i-1][j] + C[i-1][j-1]) % mod;
    }

    dp2[0][0] = 1;    
    for(int i = 1; i < maxn; i++){
	for(int j = 0; j <= i; j++){
	    if(j + 2 <= i)
		dp2[i][j] = (1ll * dp2[i][j] + 1ll * C[i-j][2] * dp2[i-1][j+1]) % mod;
	    if(j >= 1)
		dp2[i][j] = (1ll * dp2[i][j] + 1ll * C[i+j][2] * dp2[i-1][j-1]) % mod;
	    if(j < i)
		dp2[i][j] = (1ll * dp2[i][j] + 1ll * (i-j) * (i+j) % mod * dp2[i-1][j]) % mod;
	}
    }

    for(int i = 1; i < maxn; i++){
	F[i] = dp2[i][0];
	for(int j = 1; j < i; j++){
	    F[i] = (1ll * F[i] - 1ll * C[i-1][j-1] %mod * C[i][j] %mod * F[j] % mod * dp2[i-j][0]) % mod;
	}
	F[i] = (F[i] + mod) % mod;
    }
    
    int n;
    cin >> n;
    for(int i = 1; i <= n; i++){
	int x;
	cin >> x;
	is[x] = 1;
    }
    int cnt = 0;
    for(int i = 2*n; i >= 1; i--){
	cnt+= is[i] ? 1 : -1;
	if(cnt < 0)
	    return cout << 0 << endl, 0;
    }
    
    dp[0][0] = 1;
    for(int i = 1; i <= n; i++){
	int A = 0, B = 0;
	for(int j = 2*n; j >= 1; j--){
	    if(is[j]){
		if(++A == i)
		    break;
	    }
	    else{
		++B;
	    }
	}
	for(int j = i; j >= 0; j--){
	    if(B > i-j)
		continue;
	    int extra = i-j - B;
	    if(j > 0)
		dp[i][j] = (dp[i][j] + dp[i-1][j-1]) % mod;
	    for(int k = 1; k + j <= i && k <= extra; k++){
		dp[i][j] = (1ll * dp[i][j] + 1ll * C[j + k-1][k-1] * F[k] % mod * C[extra][k] % mod * dp[i-1][j + k-1]) % mod;
	    }
	}
    }
    return cout << dp[n][0] << endl, 0;
}

Subtask #1
6.0 / 6.0

# Verdict Execution time Memory Grader output
1 Correct 30 ms 11896 KB Output is correct
2 Correct 30 ms 11896 KB Output is correct
3 Correct 30 ms 11896 KB Output is correct
4 Correct 29 ms 11896 KB Output is correct
5 Correct 30 ms 11904 KB Output is correct
6 Correct 32 ms 11896 KB Output is correct
7 Correct 30 ms 11904 KB Output is correct
8 Correct 30 ms 11936 KB Output is correct
9 Correct 32 ms 11896 KB Output is correct
10 Correct 30 ms 11896 KB Output is correct

Subtask #2
52.0 / 52.0

# Verdict Execution time Memory Grader output
1 Correct 30 ms 11896 KB Output is correct
2 Correct 30 ms 11896 KB Output is correct
3 Correct 30 ms 11896 KB Output is correct
4 Correct 29 ms 11896 KB Output is correct
5 Correct 30 ms 11904 KB Output is correct
6 Correct 32 ms 11896 KB Output is correct
7 Correct 30 ms 11904 KB Output is correct
8 Correct 30 ms 11936 KB Output is correct
9 Correct 32 ms 11896 KB Output is correct
10 Correct 30 ms 11896 KB Output is correct
11 Correct 30 ms 12024 KB Output is correct
12 Correct 33 ms 12104 KB Output is correct
13 Correct 30 ms 12032 KB Output is correct
14 Correct 30 ms 11896 KB Output is correct
15 Correct 37 ms 11896 KB Output is correct
16 Correct 30 ms 12024 KB Output is correct
17 Correct 34 ms 11896 KB Output is correct
18 Correct 37 ms 12024 KB Output is correct
19 Correct 31 ms 12032 KB Output is correct
20 Correct 32 ms 12024 KB Output is correct

Subtask #3
42.0 / 42.0

# Verdict Execution time Memory Grader output
1 Correct 30 ms 11896 KB Output is correct
2 Correct 30 ms 11896 KB Output is correct
3 Correct 30 ms 11896 KB Output is correct
4 Correct 29 ms 11896 KB Output is correct
5 Correct 30 ms 11904 KB Output is correct
6 Correct 32 ms 11896 KB Output is correct
7 Correct 30 ms 11904 KB Output is correct
8 Correct 30 ms 11936 KB Output is correct
9 Correct 32 ms 11896 KB Output is correct
10 Correct 30 ms 11896 KB Output is correct
11 Correct 30 ms 12024 KB Output is correct
12 Correct 33 ms 12104 KB Output is correct
13 Correct 30 ms 12032 KB Output is correct
14 Correct 30 ms 11896 KB Output is correct
15 Correct 37 ms 11896 KB Output is correct
16 Correct 30 ms 12024 KB Output is correct
17 Correct 34 ms 11896 KB Output is correct
18 Correct 37 ms 12024 KB Output is correct
19 Correct 31 ms 12032 KB Output is correct
20 Correct 32 ms 12024 KB Output is correct
21 Correct 34 ms 14328 KB Output is correct
22 Correct 33 ms 14328 KB Output is correct
23 Correct 40 ms 14328 KB Output is correct
24 Correct 36 ms 14328 KB Output is correct
25 Correct 38 ms 11900 KB Output is correct
26 Correct 30 ms 11896 KB Output is correct
27 Correct 30 ms 11904 KB Output is correct
28 Correct 33 ms 14200 KB Output is correct
29 Correct 30 ms 11812 KB Output is correct
30 Correct 370 ms 14584 KB Output is correct
31 Correct 198 ms 14572 KB Output is correct
32 Correct 271 ms 14584 KB Output is correct
33 Correct 346 ms 14584 KB Output is correct
34 Correct 197 ms 14712 KB Output is correct
35 Correct 278 ms 14764 KB Output is correct
36 Correct 343 ms 14584 KB Output is correct