제출 #735810

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
735810		danikoynov	캥거루 (CEOI16_kangaroo)	C++14	51 / 100	503 ms	149732 KiB

kangaroo

/**
 ____ ____ ____ ____ ____ ____
||l |||e |||i |||n |||a |||d ||
||__|||__|||__|||__|||__|||__||
|/__\|/__\|/__\|/__\|/__\|/__\|

**/

#include<bits/stdc++.h>
#define endl '\n'

using namespace std;
typedef long long ll;

void speed()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
}

const int maxn = 210;
const ll mod = 1e9 + 7;
int n, s, f;
ll a[maxn][maxn][maxn];
ll d[maxn][maxn][maxn];

void add(ll &cell, ll val)
{
    cell += val;
    if (cell >= mod)
        cell -= mod;
}

void solve()
{
    cin >> n >> s >> f;
    if (s > f)
        swap(s, f);

    a[1][1][1] = d[1][1][1] = 1;
    for (int l = 2; l <= n; l ++)
    {
        for (int i = 1; i <= l; i ++)
        {
            for (int j = 1; j <= l; j ++)
            {
                if (i == j)
                    continue;
                if (i > 1 && i < j)
                {
                    a[l][i][j] = (a[l][i - 1][j] - d[l - 1][i - 1][j - 1] + mod) % mod;
                }
                else if (i > j + 1)
                {
                    a[l][i][j] = (a[l][i - 1][j] - d[l - 1][i - 1][j] + mod) % mod;
                }
                else
                {
                    for (int g = i + 1; g <= n; g ++)
                    {
                        ll val = d[l - 1][g - 1][j - 1];
                        if (j < i)
                            val = d[l - 1][g - 1][j];
                        add(a[l][i][j], val);
                    }
                }

                for (int g = i - 1; g >= 0; g --)
                {
                    ll val = a[l - 1][g][j];
                    if (j > i)
                        val = a[l - 1][g][j - 1];
                    add(d[l][i][j], val);
                }

                ///cout << l << " " << i << " " << j << " " << a[l][i][j] << " " << d[l][i][j] << endl;
            }
        }
    }

    ll ans = (d[n][s][f] + a[n][s][f]) % mod;
    cout << ans << endl;

}

int main()
{
    solve();
    return 0;
}

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