URAL1017. Staircases

链接

简单递推

 #include <iostream>
 #include<cstdio>
 #include<cstring>
 #include<algorithm>
 #include<stdlib.h>
 using namespace std;
 #define LL long long
 LL dp[][];
 int main()
 {
     int i,j,n,g;
     LL ans=;
     scanf("%d",&n);
     for(i = ; i <= n ;i++)
     dp[i][i] = ;
     for(i = ; i <= n ;i++)
     {
         for(j =  ; j < i ; j++)
         {
             for(g =  ; g < j ; g++)
             dp[i][j]+=dp[i-j][g];
         }
     }
     for(i = ; i < n ;i++)
     ans+=dp[n][i];
     printf("%lld\n",ans);
     return ;
 }