#!/usr/bin/env tclsh
#
# Task 2: Max Score
# 
# Submitted by: Mohammad Sajid Anwar
# 
# You are given a string, $str, containing 0 and 1 only.
# 
# Write a script to return the max score after splitting the string into two
# non-empty substrings. The score after splitting a string is the number of zeros
# in the left substring plus the number of ones in the right substring.
# 
# Example 1
# 
#     Input: $str = "0011"
#     Output: 4
# 
#     1: left = "0", right = "011" => 1 + 2 => 3
#     2: left = "00", right = "11" => 2 + 2 => 4
#     3: left = "001", right = "1" => 2 + 1 => 3
# 
# Example 2
# 
#     Input: $str = "0000"
#     Output: 3
# 
#     1: left = "0", right = "000" => 1 + 0 => 1
#     2: left = "00", right = "00" => 2 + 0 => 2
#     3: left = "000", right = "0" => 3 + 0 => 3
# 
# Example 3
# 
#     Input: $str = "1111"
#     Output: 3
# 
#     1: left = "1", right = "111" => 0 + 3 => 3
#     2: left = "11", right = "11" => 0 + 2 => 2
#     3: left = "111", right = "1" => 0 + 1 => 1
# 
# Example 4
# 
#     Input: $str = "0101"
#     Output: 3
# 
#     1: left = "0", right = "101" => 1 + 2 => 3
#     2: left = "01", right = "01" => 1 + 1 => 2
#     3: left = "010", right = "1" => 2 + 1 => 3
# 
# Example 5
# 
#     Input: $str = "011101"
#     Output: 5
# 
#     1: left = "0", right = "11101" => 1 + 4 => 5
#     2: left = "01", right = "1101" => 1 + 3 => 4
#     3: left = "011", right = "101" => 1 + 2 => 3
#     4: left = "0111", right = "01" => 1 + 1 => 2
#     5: left = "01110", right = "1" => 2 + 1 => 3
# 

package require tcltest

set cases {
    {"0011"   4 "Example 1"} 
    {"0000"   3 "Example 2"} 
    {"1111"   3 "Example 3"} 
    {"0101"   3 "Example 4"} 
    {"011101" 5 "Example 5"} 
}

proc max_score {str} {
    set max 0
    for {set i 1} {$i < [string length $str]} {incr i} {
        set left [string range $str 0 [expr $i - 1]]
        set right [string range $str $i end]
        set score [expr [regexp -all {0} $left] + [regexp -all {1} $right]]
        if {$score > $max} {
            set max $score
        }
    }
    return $max
}

tcltest::configure -verbose {pass}
foreach case $cases {
    tcltest::test [lindex $case 2] {} {
        max_score [lindex $case 0]
    } [lindex $case 1]
}

exit 0