Josephus Problem in Tcl

Welcome to the Josephus Problem in Tcl page! Here, you'll find the source code for this program as well as a description of how the program works.

Current Solution

proc usage {} {
    puts stderr {Usage: please input the total number of people and number of people to skip.}
    exit 1
}

proc parseInt {s} {
    set s [string trim $s]
    if {[string is integer -strict $s]} { return $s }
    usage
}

proc josephus {total skip} {
    if {$skip < 1 || $total < 1} { usage }

    # If skip = 1, survivor is the last person
    if {$skip == 1} { return $total }

    # Optimized case for skip = 2
    if {$skip == 2} {
        set power 1
        while {($power << 1) <= $total} {
            set power [expr {$power << 1}]
        }
        return [expr {2 * ($total - $power) + 1}]
    }

    set result 0
    for {set i 2} {$i <= $total} {incr i} {
        set result [expr {($result + $skip) % $i}]
    }

    return [expr {$result + 1}]
}

if {$argc != 2} { usage }

set total [parseInt [lindex $argv 0]]
set skip  [parseInt [lindex $argv 1]]

puts [josephus $total $skip]

Josephus Problem in Tcl was written by:

• Ștefan-Iulian Alecu

If you see anything you'd like to change or update, please consider contributing.

How to Implement the Solution

No 'How to Implement the Solution' section available. Please consider contributing.

How to Run the Solution

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