Test results - Codility

Tasks Details

medium

1. CountDiv

Compute number of integers divisible by k in range [a..b].

Task Score

100%

Correctness

100%

Performance

100%

Write a function:

fun solution(A: Int, B: Int, K: Int): Int

that, given three integers A, B and K, returns the number of integers within the range [A..B] that are divisible by K, i.e.:

{ i : A ≤ i ≤ B, i mod K = 0 }

For example, for A = 6, B = 11 and K = 2, your function should return 3, because there are three numbers divisible by 2 within the range [6..11], namely 6, 8 and 10.

Write an efficient algorithm for the following assumptions:

A and B are integers within the range [0..2,000,000,000];

K is an integer within the range [1..2,000,000,000];

A ≤ B.

Solution

Programming language used Kotlin

Time spent on task 3 minutes

Notes

not defined yet

Code: 22:02:18 UTC, java, autosave

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// you can also use imports, for example:
// import java.util.*;

// you can write to stdout for debugging purposes, e.g.
// System.out.println("this is a debug message");

class Solution {
    public int solution(int A, int B, int K) {
        // write your code in Java SE 8
    }
}

Code: 22:02:26 UTC, kt, autosave

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// you can also use imports, for example:
// import kotlin.math.*

// you can write to stdout for debugging purposes, e.g.
// println("this is a debug message")

fun solution(A: Int, B: Int, K: Int): Int {
    // write your code in Kotlin
}

Code: 22:03:16 UTC, kt, autosave

show code in pop-up

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// you can also use imports, for example:
// import kotlin.math.*

// you can write to stdout for debugging purposes, e.g.
// println("this is a debug message")

fun solution(A: Int, B: Int, K: Int): Int {
    // write your code in Kotlin
}

private fun Boolean.toInt(): Int {
        return if (this) 1 else 0
    }

Code: 22:03:26 UTC, kt, autosave

show code in pop-up

1 2 3 4 5 6 7 8 9 10 11 12 13

// you can also use imports, for example:
// import kotlin.math.*

// you can write to stdout for debugging purposes, e.g.
// println("this is a debug message")

fun solution(A: Int, B: Int, K: Int): Int {
    // write your code in Kotlin
}

private fun Boolean.toInt(): Int {
    return if (this) 1 else 0
}

Code: 22:03:44 UTC, kt, autosave

show code in pop-up

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

// you can also use imports, for example:
// import kotlin.math.*

// you can write to stdout for debugging purposes, e.g.
// println("this is a debug message")

fun solution(A: Int, B: Int, K: Int): Int {
    // write your code in Kotlin
    var newA = A
        while (newA % K != 0 && newA < B)
            newA++

        var newB = B
        while (newB % K != 0 && newB > newA)
            newB--

        if (newA == newB) {
            return (newA % K == 0).toInt()
        }

        //println("(newA, newB) = $newA, $newB")
        val result = ((newB - newA + K.toLong()) / K.toDouble()).toInt()
        return max(result, 0)
}

private fun Boolean.toInt(): Int {
    return if (this) 1 else 0
}

Code: 22:03:47 UTC, kt, verify, result: Failed

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// you can also use imports, for example:
// import kotlin.math.*

// you can write to stdout for debugging purposes, e.g.
// println("this is a debug message")

fun solution(A: Int, B: Int, K: Int): Int {
    // write your code in Kotlin
    var newA = A
    while (newA % K != 0 && newA < B)
        newA++

    var newB = B
    while (newB % K != 0 && newB > newA)
        newB--

    if (newA == newB) {
        return (newA % K == 0).toInt()
    }

    //println("(newA, newB) = $newA, $newB")
    val result = ((newB - newA + K.toLong()) / K.toDouble()).toInt()
    return max(result, 0)
}

private fun Boolean.toInt(): Int {
    return if (this) 1 else 0
}

Analysis

Compile error

solution.kt:23:12: error: unresolved reference: max
    return max(result, 0)
           ^

Code: 22:04:03 UTC, kt, verify, result: Passed

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// you can also use imports, for example:
// import kotlin.math.*

// you can write to stdout for debugging purposes, e.g.
// println("this is a debug message")

fun solution(A: Int, B: Int, K: Int): Int {
    // write your code in Kotlin
    var newA = A
    while (newA % K != 0 && newA < B)
        newA++

    var newB = B
    while (newB % K != 0 && newB > newA)
        newB--

    if (newA == newB) {
        return (newA % K == 0).toInt()
    }

    //println("(newA, newB) = $newA, $newB")
    val result = ((newB - newA + K.toLong()) / K.toDouble()).toInt()
    return Math.max(result, 0)
}

private fun Boolean.toInt(): Int {
    return if (this) 1 else 0
}

Analysis

expand all Example tests

▶

example
A = 6, B = 11, K = 2

✔

0.004 s

Code: 22:04:40 UTC, kt, verify, result: Passed

show code in pop-up

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// you can also use imports, for example:
// import kotlin.math.*

// you can write to stdout for debugging purposes, e.g.
// println("this is a debug message")

fun solution(A: Int, B: Int, K: Int): Int {
    // write your code in Kotlin
    var newA = A
    while (newA % K != 0 && newA < B)
        newA++

    var newB = B
    while (newB % K != 0 && newB > newA)
        newB--

    if (newA == newB) {
        return (newA % K == 0).toInt()
    }

    //println("(newA, newB) = $newA, $newB")
    val result = ((newB - newA + K.toLong()) / K.toDouble()).toInt()
    return Math.max(result, 0)
}

private fun Boolean.toInt(): Int {
    return if (this) 1 else 0
}

Analysis

expand all Example tests

▶

example
A = 6, B = 11, K = 2

✔

0.004 s

Code: 22:04:51 UTC, kt, final, score: 100

show code in pop-up

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

// you can also use imports, for example:
// import kotlin.math.*

// you can write to stdout for debugging purposes, e.g.
// println("this is a debug message")

fun solution(A: Int, B: Int, K: Int): Int {
    // write your code in Kotlin
    var newA = A
    while (newA % K != 0 && newA < B)
        newA++

    var newB = B
    while (newB % K != 0 && newB > newA)
        newB--

    if (newA == newB) {
        return (newA % K == 0).toInt()
    }

    //println("(newA, newB) = $newA, $newB")
    val result = ((newB - newA + K.toLong()) / K.toDouble()).toInt()
    return Math.max(result, 0)
}

private fun Boolean.toInt(): Int {
    return if (this) 1 else 0
}

Analysis summary

The solution obtained perfect score.

Analysis

Detected time complexity:

O(1)

expand all Example tests

▶

example
A = 6, B = 11, K = 2

✔

0.004 s

expand all Correctness tests

▶

simple
A = 11, B = 345, K = 17

✔

0.004 s

▶

minimal
A = B in {0,1}, K = 11

✔

0.004 s

▶

extreme_ifempty
A = 10, B = 10, K in {5,7,20}

✔

0.004 s

▶

extreme_endpoints
verify handling of range endpoints, multiple runs

✔

0.004 s

expand all Performance tests

▶

big_values
A = 100, B=123M+, K=2

✔

0.004 s

▶

big_values2
A = 101, B = 123M+, K = 10K

✔

0.008 s

▶

big_values3
A = 0, B = MAXINT, K in {1,MAXINT}

✔

0.004 s

▶

big_values4
A, B, K in {1,MAXINT}

✔

0.004 s

0.008 s