Submission #222695

#	Time	Username	Problem	Language	Result	Execution time	Memory
222695		Minnakhmetov	Kangaroo (CEOI16_kangaroo)	C++14	6 / 100	6 ms	1664 KiB

kangaroo

#include <bits/stdc++.h>
using namespace std;

#define ll long long
#define all(aaa) aaa.begin(), aaa.end()

const int N = 205, MOD = 1e9 + 7;
int dp[N][N][N][2], pref[N][N][N][2];

void add(int &a, int b) {
	a += b;
	if (a >= MOD)
		a -= MOD;
}

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

    int n, cs, cf;
    cin >> n >> cs >> cf;

    dp[2][2][1][1]++;
    dp[2][1][2][0]++;

    pref[2][2][1][1]++;
    pref[2][2][2][1]++;
    pref[2][1][2][0]++;

    for (int i = 3; i <= n; i++) {
        for (int k = 1; k <= i; k++) {
    	   for (int j = 1; j <= i; j++) {
    			if (j != k) {
                    add(dp[i][k][j][0], pref[i - 1][k - (k > j)][j - 1][1]);
                    add(dp[i][k][j][1], pref[i - 1][k - (k > j)][i - 1][0]);
                    add(dp[i][k][j][1], -pref[i - 1][k - (k > j)][j - 1][0]);
    			}
                pref[i][k][j][0] = pref[i][k][j - 1][0];
                pref[i][k][j][1] = pref[i][k][j - 1][1];
                add(pref[i][k][j][0], dp[i][k][j][0]);
                add(pref[i][k][j][1], dp[i][k][j][1]);
    		}
    	}
    }

    int ans = (dp[n][cf][cs][0] + dp[n][cf][cs][1]) % MOD;

    cout << ans;

    return 0;
}

• Subtask 1: 6 / 6
• Subtask 2: 0 / 30
• Subtask 3: 0 / 15
• Subtask 4: 0 / 49