AirBnB OA | SDE | Set - 3 | DP | April 2023

Question

There are 'n' stones in a row from 0 to n-1. For every ith stone , there are 2 values associated with it, a[i] and b[i] . You have to remove all the stones from the row one by one. Removing the ith stone follows the rule :

 

1.  

   If (i-1)th and (i+1)th stones are still present , then , cost of removing the ith stone is b[i].

    

2.  

   if either (i-1)th or (i+1)th stone is present , then cost of removing the ith stone is a[i].

    

3.  

   if neither (i-1)th nor (i+1)th stone is present , the cost of removing the ith stone is 0.

    

 

Find the minimum total cost of removing all the stones.

 

Constraints :
1 <= n <= 50000
1 <= a[i] , b[i] <= 1000