Submission #609403

#	Time	Username	Problem	Language	Result	Execution time	Memory
609403		SlavicG	Kangaroo (CEOI16_kangaroo)	C++17	100 / 100	22 ms	24012 KiB

kangaroo

#include <iostream>
int64_t n,s,t,m=1e9+7,d[5000][5000],i,j;
main() {
    std::cin>>n>>s>>t;
    d[0][0]=1;
    for(i=1;i<=n;++i){
        for(int j=1;j<=i;++j){
            if(i==s||i==t)d[i][j]=d[i-1][j-1]+d[i-1][j]%m;
            else d[i][j]=(d[i-1][j+1]*j+d[i-1][j-1]*(j-(i>s)-(i>t)))%m;
        }
    }
    std::cout<<d[n][1];
}

Compilation message (stderr)

kangaroo.cpp:3:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
    3 | main() {
      | ^~~~

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