Step by Step solution about How to resolve the algorithm Twelve statements step by step in the Kotlin programming language

Kotlin Code Overview: This Kotlin code explores a set of 12 binary bit patterns, represented as strings of 13 characters, where the first character is ignored and the remaining 12 characters represent a bitmask. The goal is to identify bit patterns that satisfy specific conditions and highlight those that come close to matching the criteria.

Detailed Explanation:

1. Type aliases: The code defines Predicate as a type alias for a function that takes a string (the bitmask) as input and returns a Boolean indicating whether the bitmask satisfies a specific condition.

2. predicates List: This list contains 12 Predicate functions, each representing a specific condition that the bitmask should satisfy. For example:

   • { it.length == 13 }: Ensures the bitmask has a length of 13 characters.
   • { (7..12).count { i -> it[i] == '1' } == 3 }: Checks if there are exactly 3 '1' bits between positions 8 and 13.
   • { it[5] == '0' || (it[6] == '1' && it[7] == '1') }: Checks if either bit 6 or bit 7 is set to '1', but not both.

3. show Function: This function prints a visual representation of a bitmask, showing the positions of '1' bits. It indents the output if indent is true.

4. Main Function:

   • Exact Hits: This section iterates through all possible 13-bit bitmasks (represented by numbers from 0 to 4095) and checks if each bitmask satisfies all 12 predicate conditions. If all conditions are met, the bitmask is printed.
   • Near Misses: This section iterates through the same set of bitmasks again but looks for bitmasks that satisfy exactly 11 of the 12 conditions. For each near miss, it prints the statement number where the failure occurs and visualizes the bitmask.

The code essentially provides a way to explore and analyze specific patterns within binary bitmasks, making it useful for scenarios where pattern recognition or bitwise operations are involved.

// version 1.1.3

typealias Predicate = (String) -> Boolean

val predicates = listOf<Predicate>( 
    { it.length == 13 },  // indexing starts at 0 but first bit ignored
    { (7..12).count { i -> it[i] == '1' } == 3 },
    { (2..12 step 2).count { i -> it[i] == '1' } == 2 },
    { it[5] == '0' || (it[6] == '1' && it[7] == '1') }, 
    { it[2] == '0' && it[3]  == '0' && it[4] == '0' },
    { (1..11 step 2).count { i -> it[i] == '1' } == 4 },
    { (it[2] == '1') xor (it[3] == '1') },
    { it[7] == '0' || (it[5] == '1' && it[6] == '1') },
    { (1..6).count { i -> it[i] == '1' } == 3 },
    { it[11] == '1' && it[12] == '1' },
    { (7..9).count { i -> it[i] == '1' } == 1 },
    { (1..11).count { i -> it[i] == '1' } == 4 }
)

fun show(s: String, indent: Boolean) {
    if (indent) print("    ")
    for (i in s.indices) if (s[i] == '1') print("$i ")
    println()
} 

fun main(args: Array<String>) {
    println("Exact hits:")
    for (i in 0..4095) {
        val s = i.toString(2).padStart(13, '0')
        var j = 1
        if (predicates.all { it(s) == (s[j++] == '1') }) show(s, true)
    }

    println("\nNear misses:")
    for (i in 0..4095) {
        val s = i.toString(2).padStart(13, '0')
        var j = 1
        if (predicates.count { it(s) == (s[j++] == '1') } == 11) {
            var k = 1
            val iof = predicates.indexOfFirst { it(s) != (s[k++] == '1') } + 1
            print("    (Fails at statement ${"%2d".format(iof)})  ")
            show(s, false)
        }
    }    
}