Submission #893645

#	Time	Username	Problem	Language	Result	Execution time	Memory
893645		vjudge1	Kangaroo (CEOI16_kangaroo)	C++17	51 / 100	1982 ms	524288 KiB

kangaroo

#include<bits/stdc++.h>

using namespace std;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
typedef long long ll;
#define int ll
typedef unsigned long long ull;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

#define pb push_back
#define all(x) x.begin(), x.end()
#define sz(x) (int)x.size()
#define mispertion ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0)
#define F first
#define S second
#define getlast(s) (*s.rbegin())
#define debg cout << "OK\n"

const ld PI = 3.1415926535;
const int N = 2e5 + 2;
const int M = 7e6 + 1;
int mod = 1e9+7;
const int infi = INT_MAX;
const ll infl = LLONG_MAX;
const int P = 31;

int mult(int a, int b) {
    return a * 1LL * b % mod;
}

int sum(int a, int b) {
    a %= mod; 
    if (a + b < 0)
        return a + b + mod;
    if (a + b >= mod)
        return a + b - mod;
    return a + b;
}

ll binpow(ll a, ll n) {
    if (n == 0)
        return 1;
    if (n % 2 == 1) {
        return binpow(a, n - 1) * a % mod;
    } else {
        ll b = binpow(a, n / 2);
        return b * b % mod;
    }
}


void solve(){
    int n, cs, cf;
    cin >> n >> cs >> cf;
    int a[n + 1][n + 1][n + 1];
    int d[n + 1][n + 1][n + 1];
    memset(a, 0, sizeof a);
    memset(d, 0, sizeof d);
    a[2][1][2] = 1;
    d[2][2][1] = 1;
    for(int i = 3; i <= n; i++){
        for(int s = 1; s <= i; s++){
            for(int f = 1; f <= i; f++){
                if(s == f)
                    continue;
                for(int f1 = 1; f1 < f; f1++){
                    if(s > f){
                        a[i][s][f] = sum(a[i][s][f], d[i - 1][s - 1][f1]);
                    }else{
                        a[i][s][f] = sum(a[i][s][f], d[i - 1][s][f1]);
                    }
                }
                for(int f1 = f; f1 <= i; f1++){
                    if(s > f){
                        d[i][s][f] = sum(d[i][s][f], a[i - 1][s - 1][f1]);
                    }else{
                        d[i][s][f] = sum(d[i][s][f], a[i - 1][s][f1]);
                    }
                }
            }
        }
    }
    cout << sum(d[n][cs][cf], a[n][cs][cf]) << '\n';
}   

signed main() {
    mispertion;
    int t = 1;
    //cin >> t;
    while(t--){
        solve();
    }
    return 0;
}

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