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답안 #242669

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
242669 2020-06-28T22:53:09 Z kingfran1907 Zapina (COCI20_zapina) C++14
110 / 110
 382 ms 5372 KB 
#include <bits/stdc++.h>

using namespace std;
typedef long long llint;

const int maxn = 400;
const llint mod = 1e9+7;

int n;
llint dp[maxn][maxn][3];
llint fac[maxn];
llint chos[maxn][maxn];

llint f(int x, int y, bool flag) {
    if (x == n + 1) {
        if (y == 0) return flag;
        else return 0;
    }

    llint &ret = dp[x][y][flag];
    if (ret != -1) return ret;

    ret = 0;
    for (int i = 0; i <= y; i++) {
        ret += chos[y][i] * f(x + 1, y - i, flag || (i == x));
        ret %= mod;
    }
    return ret;
}

llint pot(llint a, llint b) {
    if (b == 0) return 1;
    else if (b % 2 == 1) return (a * pot(a, b - 1)) % mod;
    else {
        llint out = pot(a, b / 2);
        return (out * out) % mod;
    }
}

llint inv(llint x) {
    return pot(x, mod - 2);
}

llint choose(int a, int b) {
    llint out = fac[a];
    out *= inv(fac[b]), out %= mod;
    out *= inv(fac[a - b]), out %= mod;
    return out;
}

int main() {
    memset(dp, -1, sizeof dp);
    scanf("%d", &n);
    fac[0] = 1;
    for (int i = 1; i <= n; i++)
        fac[i] = fac[i - 1] * i, fac[i] %= mod;

    for (int i = 0; i <= n; i++) {
        for (int j = 0; j <= i; j++) {
            chos[i][j] = choose(i, j);
        }
    }
    printf("%lld\n", f(1, n, false));
    return 0;
}

Compilation message

zapina.cpp: In function 'int main()':
zapina.cpp:53:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &n);
     ~~~~~^~~~~~~~~~

Subtask #1
22.0 / 22.0

# 결과 실행 시간 메모리 Grader output
1 Correct 6 ms 4096 KB Output is correct
2 Correct 6 ms 4096 KB Output is correct
3 Correct 6 ms 4096 KB Output is correct
4 Correct 6 ms 4096 KB Output is correct
5 Correct 6 ms 4096 KB Output is correct

Subtask #2
33.0 / 33.0

# 결과 실행 시간 메모리 Grader output
1 Correct 6 ms 4096 KB Output is correct
2 Correct 6 ms 4096 KB Output is correct
3 Correct 6 ms 4096 KB Output is correct
4 Correct 6 ms 4096 KB Output is correct
5 Correct 6 ms 4096 KB Output is correct
6 Correct 6 ms 4096 KB Output is correct
7 Correct 6 ms 4096 KB Output is correct
8 Correct 6 ms 4224 KB Output is correct
9 Correct 6 ms 4096 KB Output is correct
10 Correct 7 ms 4096 KB Output is correct
11 Correct 6 ms 4224 KB Output is correct
12 Correct 6 ms 4096 KB Output is correct
13 Correct 7 ms 4096 KB Output is correct
14 Correct 7 ms 4224 KB Output is correct
15 Correct 7 ms 4096 KB Output is correct
16 Correct 7 ms 4224 KB Output is correct

Subtask #3
55.0 / 55.0

# 결과 실행 시간 메모리 Grader output
1 Correct 6 ms 4096 KB Output is correct
2 Correct 6 ms 4096 KB Output is correct
3 Correct 6 ms 4096 KB Output is correct
4 Correct 6 ms 4096 KB Output is correct
5 Correct 6 ms 4096 KB Output is correct
6 Correct 6 ms 4096 KB Output is correct
7 Correct 6 ms 4096 KB Output is correct
8 Correct 6 ms 4224 KB Output is correct
9 Correct 6 ms 4096 KB Output is correct
10 Correct 7 ms 4096 KB Output is correct
11 Correct 6 ms 4224 KB Output is correct
12 Correct 6 ms 4096 KB Output is correct
13 Correct 7 ms 4096 KB Output is correct
14 Correct 7 ms 4224 KB Output is correct
15 Correct 7 ms 4096 KB Output is correct
16 Correct 7 ms 4224 KB Output is correct
17 Correct 202 ms 5008 KB Output is correct
18 Correct 9 ms 4224 KB Output is correct
19 Correct 48 ms 4608 KB Output is correct
20 Correct 6 ms 4096 KB Output is correct
21 Correct 242 ms 5112 KB Output is correct
22 Correct 37 ms 4480 KB Output is correct
23 Correct 9 ms 4224 KB Output is correct
24 Correct 61 ms 4608 KB Output is correct
25 Correct 44 ms 4608 KB Output is correct
26 Correct 79 ms 4736 KB Output is correct
27 Correct 344 ms 5344 KB Output is correct
28 Correct 342 ms 5240 KB Output is correct
29 Correct 344 ms 5372 KB Output is correct
30 Correct 348 ms 5116 KB Output is correct
31 Correct 359 ms 5244 KB Output is correct
32 Correct 354 ms 5240 KB Output is correct
33 Correct 363 ms 5244 KB Output is correct
34 Correct 362 ms 5240 KB Output is correct
35 Correct 368 ms 5368 KB Output is correct
36 Correct 369 ms 5248 KB Output is correct
37 Correct 382 ms 5368 KB Output is correct