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Submission #1088582

# Submission time Handle Problem Language Result Execution time Memory
1088582 2024-09-14T15:50:55 Z DobromirAngelov Tents (JOI18_tents) C++14
100 / 100
 92 ms 70932 KB 
#include<bits/stdc++.h>
#define endl '\n'

using namespace std;

const int MOD=1e9+7;
const int MAXN=3005;

int h,w;
long long dp[MAXN][MAXN];
long long fact[MAXN];
long long invF[MAXN];

int fastPow(long long x,int pwr)
{
    long long ret=1;
    while(pwr>0)
    {
        if(pwr&1) ret=ret*x%MOD;
        pwr/=2;
        x=x*x%MOD;
    }
    return ret;
}

int inverse(int x)
{
    return fastPow(x,MOD-2);
}

void precomp()
{
    for(int i=0;i<=w;i++) dp[0][i]=1;
    for(int i=0;i<=h;i++) dp[i][0]=1;
    for(int i=1;i<=h;i++)
    {
        for(int j=1;j<=w;j++)
        {
            dp[i][j]=(dp[i][j-1]+i*dp[i-1][j-1]*4)%MOD;
        }
    }

    fact[0]=1;
    for(int i=1;i<MAXN;i++) fact[i]=fact[i-1]*i%MOD;
    for(int i=0;i<MAXN;i++) invF[i]=inverse(fact[i]);
}

int comb(int n,int k)
{
    return (fact[n]*invF[n-k]%MOD)*invF[k]%MOD;
}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);

    cin>>h>>w;

    precomp();

    long long ans=0;
    long long P1=1;
    for(int r=0;r<=min(h,w/2);r++)
    {
        long long cur1=comb(h,r);
        if(r>0) P1=P1*comb(w-2*r+2,2)%MOD;
        cur1=cur1*P1%MOD;
        long long P2=1;
        for(int c=0;c<=min((h-r)/2,w-2*r);c++)
        {
            long long cur2=cur1*comb(w-2*r,c)%MOD;
            if(c>0) P2=P2*comb(h-r-2*c+2,2)%MOD;
            cur2=cur2*P2%MOD;

            cur2=cur2*dp[h-r-2*c][w-2*r-c]%MOD;
            ans+=cur2;
            if(ans>=MOD) ans-=MOD;
        }
    }

    cout<<ans-1<<endl;

    return 0;
}

Subtask #1
48.0 / 48.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 464 KB Output is correct
2 Correct 1 ms 348 KB Output is correct
3 Correct 1 ms 604 KB Output is correct
4 Correct 1 ms 1116 KB Output is correct
5 Correct 1 ms 860 KB Output is correct
6 Correct 1 ms 1372 KB Output is correct
7 Correct 1 ms 860 KB Output is correct
8 Correct 1 ms 1628 KB Output is correct
9 Correct 1 ms 860 KB Output is correct
10 Correct 1 ms 1884 KB Output is correct
11 Correct 1 ms 348 KB Output is correct
12 Correct 2 ms 2396 KB Output is correct

Subtask #2
52.0 / 52.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 464 KB Output is correct
2 Correct 1 ms 348 KB Output is correct
3 Correct 1 ms 604 KB Output is correct
4 Correct 1 ms 1116 KB Output is correct
5 Correct 1 ms 860 KB Output is correct
6 Correct 1 ms 1372 KB Output is correct
7 Correct 1 ms 860 KB Output is correct
8 Correct 1 ms 1628 KB Output is correct
9 Correct 1 ms 860 KB Output is correct
10 Correct 1 ms 1884 KB Output is correct
11 Correct 1 ms 348 KB Output is correct
12 Correct 2 ms 2396 KB Output is correct
13 Correct 1 ms 348 KB Output is correct
14 Correct 4 ms 9820 KB Output is correct
15 Correct 55 ms 55164 KB Output is correct
16 Correct 4 ms 4188 KB Output is correct
17 Correct 11 ms 12976 KB Output is correct
18 Correct 18 ms 17244 KB Output is correct
19 Correct 69 ms 63056 KB Output is correct
20 Correct 52 ms 51024 KB Output is correct
21 Correct 34 ms 33876 KB Output is correct
22 Correct 36 ms 35420 KB Output is correct
23 Correct 20 ms 27228 KB Output is correct
24 Correct 92 ms 70932 KB Output is correct
25 Correct 63 ms 61268 KB Output is correct
26 Correct 70 ms 66648 KB Output is correct
27 Correct 76 ms 69200 KB Output is correct