Question

Problem Statement A String 'str' of size ' n ' is said to be a perfect string only if there is no pair of indices [i,j] such that 1≤i 0 '. You are given a binary string S of size N. Your task is to print the minimum number of operations required to make S a Perfect String. In each operation, you can choose an index ' i ' in the range [ 1,M] (where M is the current size of the string) and delete the character at the ith position. Note: - String S contains only 1's and O's. Input format: The input consist of two lines: - The first line contains an integer N. - The second line contains the string S. Input will be read from the STDIN by the candidate Output Format: Print minimum number of operations required to make S as a Perfect String. The output will be matched to the candidate's output printed on the STDOUT Constraint: 1≤N≤10 5

Print minimum number of operations required to make 8 as a Perfect $tring. The output will be matched to the candidate's output printed on the 5TD0DT Constrainti - 1≤N≤10 5
Examplet Imputi 6 010101 Outputi 2 Explanationi In the first operation delete the character at the 3rd position now the new string is "01101", in the second operation delete the eharacter at the sth position string is "0111", which is a perfect string. Hence, the answer is 2. Sample input a00 Sample Output o Instructions : - Program should take input from standard input and print output to standard output, - Your code is judged by an automated system, do not write any additional welcome/greeting messages. - "Save and Test" only checks for basic test cases, more rigorous cases will be used to judge your code while scoring. - Additional score will be given for writing optimized code both in terms of memory and execution time.

Answer 1

To make the given binary string a perfect string, we need to delete characters at certain positions. We can achieve this by iterating through the string and deleting '0' characters which come after '1' characters. The minimum number of operations required can be found by counting the number of deletions.

Step-by-step explanation:

To make the given binary string a perfect string, we need to delete characters at certain positions.

First, let's understand what a perfect string is. In a perfect string, there should not be any pair of indices [i, j] such that 1 ≤ i < j ≤ ||str|| (length of string) and str[i] = '1' and str[j] = '0'. In other words, we need to delete the '0' characters which come after '1' characters.

Here's an algorithm to find the minimum number of operations required:

1. Initialize a count variable to 0.
2. Iterate through the binary string and for each character, if it is '1', increment the count variable. If it is '0', increment a second iterator index until you find a '1' character.
3. After finding a '1' character, increment the count variable and continue the iteration.
4. At the end, the count variable will represent the minimum number of operations required.

For example, consider the binary string '010101'.

Iteration 1:
Current character: 0
Second iterator index: 1
Resultant string: '00101'

Iteration 2:
Current character: 1
Second iterator index: 3
Resultant string: '0011'

Thus, the minimum number of operations required is 2.

Answer 2

Below is a Python program that takes input from standard input and prints the minimum number of operations required to make the given binary string a perfect string.

def min_operations_to_perfect_string(N, S):

ones_count = S.count('1')

operations = 0

current_size = N

for i in range(N):

if S[i] == '1':

ones_count -= 1

else:

operations += min(ones_count, current_size - ones_count)

current_size -= 1

print(operations)

# Read input from STDIN

N = int(input().strip())

S = input().strip()

# Call the function with input values

min_operations_to_perfect_string(N, S)