Submission #860649

#	Time	Username	Problem	Language	Result	Execution time	Memory
860649		nnhzzz	Kangaroo (CEOI16_kangaroo)	C++14	100 / 100	20 ms	31836 KiB

kangaroo

// cre: Nguyen Ngoc Hung - Train VOI 2024 :>

#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <unordered_set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
#include <cstring>
#include <unordered_map>
#include <cmath>
#include <array>
#include <cassert>
#include <random>

using namespace std;

#define        __nnhzzz__  signed main()
#define          BIT(i,j)  ((i>>j)&1LL)
#define           MASK(i)  (1LL<<i)
#define            ALL(x)  (x).begin(),(x).end()
#define             SZ(x)  (int)(x).size()
#define                fi  first
#define                se  second
#define                ll  long long
#define                vi  vector<int>
#define               vvi  vector<vi>
#define               pii  pair<int,int>
#define              vpii  vector<pii>
#define REPDIS(i,be,en,j)  for(int i = (be); i<=(en); i+=j)
#define     REPD(i,be,en)  for(int i = (be); i>=(en); i--)
#define      REP(i,be,en)  for(int i = (be); i<=(en); i++)
#define               int  ll
//-------------------------------------------------------------//
const int oo = 1e9,LOG = 20,MAXN = 2e3+7,N = 1e2+3;
const int MOD = 1e9+7,MOD1 = 1e9+207,MOD2 = 1e9+407,MOD3 = 998244353;
//-------------------------------------------------------------//
template<typename T1, typename T2> bool mini(T1 &a, T2 b){if(a>b){a=b;return true;}return false;}
template<typename T1, typename T2> bool maxi(T1 &a, T2 b){if(a<b){a=b;return true;}return false;}
template<typename T> T gcd(T a, T b) { while(b) { a %= b; swap(a,b); } return a; }
template<typename T> T lcm(T a, T b) { return a/gcd(a,b)*b; }

/*
----------------------------------------------------------------
    END OF TEMPLATE
----------------------------------------------------------------
    Nguyen Ngoc Hung - nnhzzz
    Training for VOI24 gold medal
----------------------------------------------------------------
*/

int dp[MAXN][MAXN];

void solve(){
    int n,a,b; cin >> n >> a >> b;
    dp[1][1] = 1;
    REP(i,2,n){
        REP(j,1,n){
            if(i==a || i==b) dp[i][j] = (dp[i-1][j-1]+dp[i-1][j])%MOD;
            else dp[i][j] = (1LL*dp[i-1][j+1]*j%MOD+1LL*dp[i-1][j-1]*(j-(i>a)-(i>b))%MOD)%MOD;
        }
    }
    cout << dp[n][1];
}

__nnhzzz__{
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    #define name "test"
    if(fopen(name".inp","r")){
        freopen(name".inp","r",stdin);
        freopen(name".out","w",stdout);
    }
    #define name1 "nnhzzz"
    if(fopen(name1".inp","r")){
        freopen(name1".inp","r",stdin);
        freopen(name1".out","w",stdout);
    }

    int test = 1;

    while(test--){
      solve();
    }
    cerr << "\nTime elapsed: " << 1000*clock()/CLOCKS_PER_SEC << "ms\n";
    return 0;
}

Compilation message (stderr)

kangaroo.cpp: In function 'int main()':
kangaroo.cpp:98:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   98 |         freopen(name".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
kangaroo.cpp:99:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   99 |         freopen(name".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
kangaroo.cpp:103:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  103 |         freopen(name1".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
kangaroo.cpp:104:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  104 |         freopen(name1".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

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