oj.uz

답안 #257230

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
257230 2020-08-03T23:54:41 Z NaimSS 캥거루 (CEOI16_kangaroo) C++14
100 / 100
 60 ms 32384 KB 
#include <bits/stdc++.h>
#define ld long double
#define endl "\n"
#define fastio ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define pb(x) push_back(x)
#define mp(a,b) make_pair(a,b)
#define ms(v,x) memset(v,x,sizeof(v))
#define all(v) v.begin(),v.end()
#define ff first
#define ss second
#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define per(i, a, b) for(int i = b-1; i>=a ; i--)
#define trav(a, x) for(auto& a : x)
#define allin(a , x) for(auto a : x)
#define td(v) v.begin(),v.end()
#define sz(v) (int)v.size()
//#define int long long
using namespace std;
typedef vector<int> vi;
#define y1 abacaba
#define left sefude
#define db(x) cerr << #x <<" == "<<x << endl;
#define db2(x,y) cerr<<#x <<" == "<<x<<", "<<#y<<" == "<<y<<endl;
typedef long long ll;
typedef pair<int,int> pii;
inline ll mod(ll n, ll m ){ ll ret = n%m; if(ret < 0) ret += m; return ret; }
ll gcd(ll a, ll b){return (b == 0LL ? a : gcd(b, a%b));}
ll exp(ll a,ll b,ll m){
    if(b==0LL) return 1LL;
    if(b==1LL) return mod(a,m);
    ll k = mod(exp(a,b/2,m),m);
    if(b&1LL){
        return mod(a*mod(k*k,m),m);
    }
    else return mod(k*k,m);
}

int n;

const int N = 2020;
const int M = 1e9 + 7;
ll dp[N][N];
int cs,cf;

ll C(int j){
  return (1ll*j*(j-1)/2)%M;
}

ll solve(int i,int j){// to em i em tem j componentes
  if(j < 0)return 0;
  ll &x = dp[i][j];
  
  if(x!=-1)return x;
  
  x = 0;
  int bad = (i>=cs) + (i>=cf);
  if(i == n + 1){
    return x = (j == 1);
  }

  if(i == cs || i == cf){
    return x = (solve(i+1,j) + solve(i+1,j+1))%M;
  }

  // tem j+1 gaps pra criar um cara, mas n pode usar o start/end
  x = (x + 1ll*solve(i+1,j+1)*(j + 1 - bad))%M;  
  // pode juntar o (1,2) ou (2,3) ... (j-1,j)
  x = (x + solve(i+1,j-1)*(j-1));

  return mod(x,M);
}

int32_t main(){
  fastio;
  cin >> n;
  cin >> cs >> cf;
  ms(dp,-1);
  cout << solve(2,1) << endl;
  // math -> gcd it all
  // Did u check N=1? Did you switch N,M?
}

Subtask #1
6.0 / 6.0

# 결과 실행 시간 메모리 Grader output
1 Correct 17 ms 32280 KB Output is correct
2 Correct 22 ms 32256 KB Output is correct

Subtask #2
30.0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 17 ms 32280 KB Output is correct
2 Correct 22 ms 32256 KB Output is correct
3 Correct 22 ms 32256 KB Output is correct
4 Correct 15 ms 32256 KB Output is correct
5 Correct 19 ms 32256 KB Output is correct
6 Correct 15 ms 32256 KB Output is correct
7 Correct 22 ms 32256 KB Output is correct
8 Correct 15 ms 32256 KB Output is correct
9 Correct 15 ms 32256 KB Output is correct
10 Correct 16 ms 32256 KB Output is correct
11 Correct 16 ms 32256 KB Output is correct

Subtask #3
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 17 ms 32280 KB Output is correct
2 Correct 22 ms 32256 KB Output is correct
3 Correct 22 ms 32256 KB Output is correct
4 Correct 15 ms 32256 KB Output is correct
5 Correct 19 ms 32256 KB Output is correct
6 Correct 15 ms 32256 KB Output is correct
7 Correct 22 ms 32256 KB Output is correct
8 Correct 15 ms 32256 KB Output is correct
9 Correct 15 ms 32256 KB Output is correct
10 Correct 16 ms 32256 KB Output is correct
11 Correct 16 ms 32256 KB Output is correct
12 Correct 15 ms 32256 KB Output is correct
13 Correct 16 ms 32256 KB Output is correct
14 Correct 16 ms 32256 KB Output is correct
15 Correct 16 ms 32336 KB Output is correct
16 Correct 16 ms 32256 KB Output is correct
17 Correct 17 ms 32256 KB Output is correct
18 Correct 16 ms 32256 KB Output is correct
19 Correct 16 ms 32256 KB Output is correct
20 Correct 16 ms 32256 KB Output is correct

Subtask #4
49.0 / 49.0

# 결과 실행 시간 메모리 Grader output
1 Correct 17 ms 32280 KB Output is correct
2 Correct 22 ms 32256 KB Output is correct
3 Correct 22 ms 32256 KB Output is correct
4 Correct 15 ms 32256 KB Output is correct
5 Correct 19 ms 32256 KB Output is correct
6 Correct 15 ms 32256 KB Output is correct
7 Correct 22 ms 32256 KB Output is correct
8 Correct 15 ms 32256 KB Output is correct
9 Correct 15 ms 32256 KB Output is correct
10 Correct 16 ms 32256 KB Output is correct
11 Correct 16 ms 32256 KB Output is correct
12 Correct 15 ms 32256 KB Output is correct
13 Correct 16 ms 32256 KB Output is correct
14 Correct 16 ms 32256 KB Output is correct
15 Correct 16 ms 32336 KB Output is correct
16 Correct 16 ms 32256 KB Output is correct
17 Correct 17 ms 32256 KB Output is correct
18 Correct 16 ms 32256 KB Output is correct
19 Correct 16 ms 32256 KB Output is correct
20 Correct 16 ms 32256 KB Output is correct
21 Correct 19 ms 32256 KB Output is correct
22 Correct 20 ms 32256 KB Output is correct
23 Correct 20 ms 32384 KB Output is correct
24 Correct 56 ms 32384 KB Output is correct
25 Correct 51 ms 32384 KB Output is correct
26 Correct 52 ms 32384 KB Output is correct
27 Correct 60 ms 32384 KB Output is correct
28 Correct 35 ms 32384 KB Output is correct