View Compilation Error

0_0_13598739_25552.cpp: In function 'int main()':
0_0_13598739_25552.cpp:50:19: error: 'len' was not declared in this scope
             for(j=len;j>=1;j--)
                   ^
0_0_13598739_25552.cpp:54:29: error: 'len' was not declared in this scope
         printf("%.2lf\n",dp[len]);
                             ^