Submission #442635

#	Time	Username	Problem	Language	Result	Execution time	Memory
442635		parsabahrami	Kangaroo (CEOI16_kangaroo)	C++17	100 / 100	39 ms	15976 KiB

kangaroo

/* I do it for the glory */
#include <bits/stdc++.h>
 
using namespace std;

typedef long long int ll;
typedef pair<int, int> pii;
 
#define SZ(x)                       (int) x.size()
#define F                           first
#define S                           second

const int N = 2e3 + 10, MOD = 1e9 + 7;
int n, s, e, dp[N][N];

int main() {
    scanf("%d%d%d", &n, &s, &e);
    dp[1][1] = 1;
    for (int i = 2; i <= n; i++) {
        for (int j = 1; j <= n; j++) {
            if (i == s || i == e) dp[i][j] = (dp[i - 1][j - 1] + dp[i - 1][j]) % MOD;
            else {
                int x = j;
                if (i > s) x--; 
                if (i > e) x--;
                dp[i][j] = (1ll * dp[i - 1][j + 1] * j % MOD + dp[i - 1][j - 1] * 1ll * x % MOD) % MOD;
            }
        }
    }
    printf("%d\n", dp[n][1]);
    return 0;
}

Compilation message (stderr)

kangaroo.cpp: In function 'int main()':
kangaroo.cpp:17:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   17 |     scanf("%d%d%d", &n, &s, &e);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 6 / 6
• Subtask 2: 30 / 30
• Subtask 3: 15 / 15
• Subtask 4: 49 / 49