Submission #1225399

#	Time	Username	Problem	Language	Result	Execution time	Memory
1225399		MarwenElarbi	Kangaroo (CEOI16_kangaroo)	C++17	0 / 100	1 ms	832 KiB

kangaroo

#include <bits/stdc++.h>
using namespace std;
const int nax=2e3+5;
const int MOD=1e9+7;
long long dp[nax][nax];
int main() {
    #ifndef ONLINE_JUDGE
        freopen("input.txt","r",stdin);
        freopen("output.txt","w",stdout);
    #endif
    int n,l,r;
    cin>>n>>l>>r;
    if(l>r) swap(l,r);
    dp[0][0]=1;
    for (int i = 1; i <= n; ++i)
    {
        for (int j = 0; j <= n-i+1; ++j)
        {
            if(j>0) dp[i][j]+=dp[i-1][j-1];
            if(i<l){
                dp[i][j]+=dp[i-1][j+1]*(j+1)*(j);
            }else if(i==l){
                dp[i][j]+=dp[i-1][j+1]*(j+1);
            }else if(i<r){
                dp[i][j]+=dp[i-1][j+1]*(j+1)*(j+1);
            }else if(i==r){
                dp[i][j]+=dp[i-1][j]*(j+1);
            }else{
                dp[i][j]+=dp[i-1][j+1]*(j+2)*(j+1);
            }
            //if(dp[i][j] > 0)cout << i << " "<<j<<" "<<dp[i][j]<<" "<<dp[i-1][j+1]<<endl;
            dp[i][j]%=MOD;
        }
    } 
    cout <<dp[n-1][0]<<endl;
}

Compilation message (stderr)

kangaroo.cpp: In function 'int main()':
kangaroo.cpp:8:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    8 |         freopen("input.txt","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
kangaroo.cpp:9:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    9 |         freopen("output.txt","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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