cf-Round #216 (Div. 2) -D Valera and Fools-dfs

#include<stdio.h>
#include<string.h>
#include<iostream>
#include<algorithm>
using namespace std;
int cnt;
int p[5001];
int s[5001];
int n,m;
int vis[5001][5001];
void dfs(int a,int b,int k)
{
    if(k>m)return;
    if(a>n)a=n+1;
    if(b>n)b=n+1;
    if(vis[a][b])return;
    vis[a][b]=1;cnt++;
   // cout<<a<<" "<<b<<endl;
   if(p[a])
   {
       if(s[b])dfs(b+1,b+2,k+1);
       if(s[b]<100)dfs(a,b+1,k+1);
   }
   if(p[a]<100)
   {
       if(s[b])dfs(b,b+1,k+1);
   }
}
int main()
{
    int i;
    while(~scanf("%d%d",&n,&m))
    {
        memset(vis,0,sizeof(vis));
        memset(p,0,sizeof(p));
        memset(s,0,sizeof(s));
        for(i=1;i<=n;i++)
        {
            scanf("%d",&p[i]);
        }
        for(i=n;i>=1;i--)
        {
            s[i]=max(s[i+1],p[i]);
        }
        cnt=0;
        if(n>1)dfs(1,2,0);
        else cnt=1;
        cout<<cnt<<endl;
    }
}