Count Asterisks

🏠 ⬅️ ➡️

You are given a string s, where every two consecutive vertical bars '|' are grouped into a pair. In other words, the 1st and 2nd '|' make a pair, the 3rd and 4th '|' make a pair, and so forth.

Return the number of '*' in s, excluding the '*' between each pair of '|'.

Note that each '|' will belong to exactly one pair.

Example 1:

Input: s = "l|*e*et|c**o|*de| " Output: 2 Explanation: The considered characters are underlined: "l|*e*et|c**o|*de| ". The characters between the first and second '|' are excluded from the answer. Also, the characters between the third and fourth '|' are excluded from the answer. There are 2 asterisks considered. Therefore, we return 2.

Example 2:

Input: s = "iamprogrammer " Output: 0 Explanation: In this example, there are no asterisks in s. Therefore, we return 0.

Example 3:

Input: s = "yo|uar|e**|b|e***au|tifu|l " Output: 5 Explanation: The considered characters are underlined: "yo|uar|e**|b|e***au|tifu|l ". There are 5 asterisks considered. Therefore, we return 5.

Constraints:

  • 1 <= s.length <= 1000
  • s consists of lowercase English letters, vertical bars '|', and asterisks '*'.
  • s contains an even number of vertical bars '|'.
Note: This problem is from LeetCode.
✅ Compiled
✅ Executed
⚠️ Correct 
program main
    implicit none
    character(len=:), allocatable :: s
    integer :: n

    s = "l|\*e\*et|c\*\*o|\*de|"
    write(*,*) "Example 1:"
    write(*,*) "Input: ", s
    n = count_asterisk(s)
    write(*,*) "Output: ", n
    write(*,*) ""

    s = "iamprogrammer "
    write(*,*) "Example 2:"
    write(*,*) "Input: ", s
    n = count_asterisk(s)
    write(*,*) "Output: ", n
    write(*,*) ""

    s = "yo|uar|e\*\*|b|e\*\*\*au|tifu|l "
    write(*,*) "Example 3:"
    write(*,*) "Input: ", s
    n = count_asterisk(s)
    write(*,*) "Output: ", n
    write(*,*) ""

contains

    function count_asterisk(str) result(n)
        implicit none
        character(len=*), intent(in) :: str
        integer :: i, j, n

        n = 0
        do i = 1, len(str)-1, 2
            if (str(i:i+1) == "|") then
                cycle
            end if
            do j = i+2, len(str)-1, 2
                if (str(j:j+1) == "|") then
                    exit
                end if
                if (str(j:j+1) == "*") then
                    n = n + 1
                end if
            end do
        end do
    end function count_asterisk

end program main
✅ Compiled
❌ Executed
❌ Correct 
! Declare variables
integer :: i, j, k, n, m
character(len=1000) :: s

! Read input
read(*,*) s

! Initialize variables
n = 0
m = 0

! Loop through the string
do i = 1, len_trim(s)
    ! Check if the current character is an asterisk
    if (s(i:i) == '*') then
        ! Increment the number of asterisks
        n = n + 1
    end if

    ! Check if the current character is a vertical bar
    if (s(i:i) == '|') then
        ! Increment the number of vertical bars
        m = m + 1

        ! Check if the current character is a vertical bar and the previous character is an asterisk
        if (s(i-1:i-1) == '*' .and. s(i+1:i+1) == '|') then
            ! Decrement the number of asterisks
            n = n - 1
        end if
    end if
end do

! Print output
write(*,*) n

end
🌐 Data from online sources 
def count_stars_except_between_pair(s: str) -> int:
    count = 0
    pipe_count = 0

    for c in s:
        if c == '|':
            pipe_count += 1
        elif c == '*' and pipe_count % 2 == 0:
            count += 1

    return count

The algorithm loops through the string with a simple for loop iterating on characters. It keeps track of the number of pipes encountered (pipeCount) and the total count of stars. If a pipe is encountered, increment pipeCount. If a star is encountered and pipeCount is even, increment the count. This condition (pipeCount % 2 == 0) ensures we are not considering stars between a pair of vertical bars. Finally, return the count of stars after processing the entire string.
🌐 Data from online sources 
int countStarsExceptBetweenPair(const std::string& s) {
    int count = 0;
    int pipeCount = 0;

    for (char c : s) {
        if (c == '|') {
            pipeCount++;
        } else if (c == '*' && pipeCount % 2 == 0) {
            count++;
        }
    }

    return count;
}

The algorithm loops through the string with a simple for loop iterating on characters. It keeps track of the number of pipes encountered (pipeCount) and the total count of stars. If a pipe is encountered, increment pipeCount. If a star is encountered and pipeCount is even, increment the count. This condition (pipeCount % 2 == 0) ensures we are not considering stars between a pair of vertical bars. Finally, return the count of stars after processing the entire string.