Minimum Penalty for a Shop

 You are given the customer visit log of a shop represented by a 0-indexed string customers consisting only of characters 'N' and 'Y':

• if the ith character is 'Y', it means that customers come at the ith hour
• whereas 'N' indicates that no customers come at the ith hour.

If the shop closes at the jth hour (0 <= j <= n), the penalty is calculated as follows:

• For every hour when the shop is open and no customers come, the penalty increases by 1.
• For every hour when the shop is closed and customers come, the penalty increases by 1.

Return the earliest hour at which the shop must be closed to incur a minimum penalty.

Note that if a shop closes at the jth hour, it means the shop is closed at the hour j.

 

Example 1:

Input: customers = "YYNY"
Output: 2
Explanation: 
- Closing the shop at the 0th hour incurs in 1+1+0+1 = 3 penalty.
- Closing the shop at the 1st hour incurs in 0+1+0+1 = 2 penalty.
- Closing the shop at the 2nd hour incurs in 0+0+0+1 = 1 penalty.
- Closing the shop at the 3rd hour incurs in 0+0+1+1 = 2 penalty.
- Closing the shop at the 4th hour incurs in 0+0+1+0 = 1 penalty.
Closing the shop at 2nd or 4th hour gives a minimum penalty. Since 2 is earlier, the optimal closing time is 2.

Example 2:

Input: customers = "NNNNN"
Output: 0
Explanation: It is best to close the shop at the 0th hour as no customers arrive.

Example 3:

Input: customers = "YYYY"
Output: 4
Explanation: It is best to close the shop at the 4th hour as customers arrive at each hour.

 

Constraints:

• 1 <= customers.length <= 105
• customers consists only of characters 'Y' and 'N'.

Solution : 

class Solution { public:     int bestClosingTime(string s) {               s.push_back('N');         vector<int>yes;         vector<int>no;         int size = s.length();         int sum_yes =0;         int sum_no =0;         for(int i  =0 ; i < size ; i++)         {             if(s[i] == 'Y')             {                 sum_yes += 1;             }             else             {                 sum_no += 1;             }             yes.push_back(sum_yes);             no.push_back(sum_no);         }         int palenty = yes[size -1];         int index = 0;         for(int  i =1 ; i < size ; i++)         {             int temp_panelty = yes[size-1] - yes[i-1]+no[i-1];             if(temp_panelty < palenty)             {                  palenty = temp_panelty;                 index = i;             }         }         return index;           } };