1892821_wa.cpp

北大大牛代码 1240道题的原代码 超级权威

# include <stdio.h>

int  v[2001], n;
long sum;

long max(long a, long b)
{
 return a>b?a:b;
}
long f(int x, int y, int m, long s)
{ 
 if(x == y) {s+=m*v[x];return s;}
 if(v[x] < v[y])
   {
    s+=m*v[x];
    x++;
    f(x,y,m+1,s);
   }
  else  if(v[x] > v[y])
   {
    s+=m*v[y];
    y--;
    f(x,y,m+1,s);
   }
  else s += max(f(x+1,y,m+1,s),f(x,y-1,m+1,s));
}
int main()
{
  int i, j;

  scanf("%d",&n);
  for(i = 0; i < n; i++)
   scanf("%d",&v[i]);
  sum = 0;
  i = 0; j = n - 1;
 printf("%ld\n",f(i,j,1,0));
}