oj.uz

Submission #370922

# Submission time Handle Problem Language Result Execution time Memory
370922 2021-02-25T05:16:19 Z 79brue Tents (JOI18_tents) C++14
100 / 100
 247 ms 71020 KB 
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
const ll MOD = 1000000007;

ll mpow(ll x, ll y){
    if(!y) return 1;
    if(y&1) return mpow(x, y-1) * x % MOD;
    ll tmp = mpow(x, y/2);
    return tmp*tmp%MOD;
}

int n, m;
ll fact[10002];
ll factInv[10002];
ll arr[10002];
ll DP[3002][3002];
ll ans;

ll comb(ll x, ll y){
    if(x<y) return 0;
    return fact[x] * factInv[y] % MOD * factInv[x-y] % MOD;
}

int main(){
    scanf("%d %d", &n, &m);

    fact[0] = 1;
    for(int i=1; i<=10000; i++) fact[i] = fact[i-1] * i % MOD;
    factInv[10000] = mpow(fact[10000], MOD-2);
    for(int i=9999; i>=0; i--) factInv[i] = factInv[i+1] * (i+1) % MOD;

    for(int i=0; i<=3000; i++){
        arr[i] = 1;
        for(int j=0; j<i; j++){
            arr[i] = arr[i] * comb(2*(i-j), 2) % MOD;
        }
    }

    for(int i=0; i<=n; i++){
        for(int j=0; j<=m; j++){
            if(i==0 || j==0){
                DP[i][j] = 1;
                continue;
            }
            DP[i][j] = DP[i-1][j];
            DP[i][j] += DP[i-1][j-1] * j * 4;
            DP[i][j] %= MOD;
        }
    }

    for(int i=0; i<=n; i++){
        for(int j=0; j<=m; j++){
            if(i+2*j > n || j+2*i > m) continue;
            ll c1 = comb(n, i) * comb(m, j) % MOD;
            ll c2 = comb(n-i, j+j) * comb(m-j, i+i) % MOD;
            ll c3 = arr[i] * arr[j] % MOD;
            ll c4 = DP[n-i-j-j][m-j-i-i];
            ans += c1 * c2 % MOD * c3 % MOD * c4 % MOD;
            ans %= MOD;
        }
    }
    printf("%lld", ans-1);
}

Compilation message

tents.cpp: In function 'int main()':
tents.cpp:28:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   28 |     scanf("%d %d", &n, &m);
      |     ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
48.0 / 48.0

# Verdict Execution time Memory Grader output
1 Correct 46 ms 492 KB Output is correct
2 Correct 39 ms 492 KB Output is correct
3 Correct 39 ms 748 KB Output is correct
4 Correct 40 ms 1388 KB Output is correct
5 Correct 39 ms 876 KB Output is correct
6 Correct 39 ms 1644 KB Output is correct
7 Correct 40 ms 1260 KB Output is correct
8 Correct 39 ms 1644 KB Output is correct
9 Correct 39 ms 1132 KB Output is correct
10 Correct 40 ms 2028 KB Output is correct
11 Correct 39 ms 620 KB Output is correct
12 Correct 41 ms 2412 KB Output is correct

Subtask #2
52.0 / 52.0

# Verdict Execution time Memory Grader output
1 Correct 46 ms 492 KB Output is correct
2 Correct 39 ms 492 KB Output is correct
3 Correct 39 ms 748 KB Output is correct
4 Correct 40 ms 1388 KB Output is correct
5 Correct 39 ms 876 KB Output is correct
6 Correct 39 ms 1644 KB Output is correct
7 Correct 40 ms 1260 KB Output is correct
8 Correct 39 ms 1644 KB Output is correct
9 Correct 39 ms 1132 KB Output is correct
10 Correct 40 ms 2028 KB Output is correct
11 Correct 39 ms 620 KB Output is correct
12 Correct 41 ms 2412 KB Output is correct
13 Correct 39 ms 620 KB Output is correct
14 Correct 43 ms 9836 KB Output is correct
15 Correct 165 ms 55532 KB Output is correct
16 Correct 43 ms 4204 KB Output is correct
17 Correct 56 ms 13036 KB Output is correct
18 Correct 78 ms 17260 KB Output is correct
19 Correct 188 ms 63212 KB Output is correct
20 Correct 168 ms 51180 KB Output is correct
21 Correct 101 ms 34156 KB Output is correct
22 Correct 113 ms 35820 KB Output is correct
23 Correct 64 ms 27244 KB Output is correct
24 Correct 247 ms 71020 KB Output is correct
25 Correct 191 ms 61548 KB Output is correct
26 Correct 218 ms 66780 KB Output is correct
27 Correct 233 ms 69100 KB Output is correct