Test results - Codility

Tasks Details

medium

1. MissingInteger

Find the smallest positive integer that does not occur in a given sequence.

Task Score

100%

Correctness

100%

Performance

100%

This is a demo task.

Write a function:

class Solution { public int solution(int[] A); }

that, given an array A of N integers, returns the smallest positive integer (greater than 0) that does not occur in A.

For example, given A = [1, 3, 6, 4, 1, 2], the function should return 5.

Given A = [1, 2, 3], the function should return 4.

Given A = [−1, −3], the function should return 1.

Write an efficient algorithm for the following assumptions:

N is an integer within the range [1..100,000];

each element of array A is an integer within the range [−1,000,000..1,000,000].

Solution

Programming language used Java 8

Time spent on task 9 minutes

Notes

not defined yet

Task timeline

Code: 07:03:41 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) {
        // write your code in Java SE 8
    }
}

Code: 07:08:30 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) {
        S
    }
}

Code: 07:08:51 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");

import java.util.Set;
import java.util.HashSet;

class Solution {
    public int solution(int[] A) {
        Set<Integer> numSet = new HashSet();
    }
}

Code: 07:10:07 UTC, java, autosave

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

// 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");

import java.util.Set;
import java.util.HashSet;

class Solution {
    public int solution(int[] A) {
        Set<Integer> numSet = new HashSet();
        
    }
}

Code: 07:10:33 UTC, java, autosave

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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22

// 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");

import java.util.Set;
import java.util.HashSet;

class Solution {
    public int solution(int[] A) {
        Set<Integer> numSet = new HashSet();
        for (int num : A) {
            if (num > 0) {
                numSet.add(num);
            }
        }
        if (numSet.size() == 0) {
            return 1;
        }
    }
}

Code: 07:10:50 UTC, java, 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

// 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");

import java.util.Set;
import java.util.HashSet;

class Solution {
    public int solution(int[] A) {
        Set<Integer> numSet = new HashSet();
        for (int num : A) {
            if (num > 0) { // Greater than 0.
                numSet.add(num);
            }
        }
        if (numSet.size() == 0) {
            return 1;
        }
    }
}

Code: 07:11:21 UTC, java, 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

// 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");

import java.util.Set;
import java.util.HashSet;

class Solution {
    public int solution(int[] A) {
        Set<Integer> numSet = new HashSet();
        for (int num : A) {
            if (num > 0) { // Greater than 0.
                numSet.add(num);
            }
        }
        // If not exists numbers, return 1.
        if (numSet.size() == 0) {
            return 1;
        }
        for (int idx = 1; idx <= Integer.MAX_VALUE; idx++) {
            
        }
    }
}

Code: 07:11:41 UTC, java, 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 29

// 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");

import java.util.Set;
import java.util.HashSet;

class Solution {
    public int solution(int[] A) {
        Set<Integer> numSet = new HashSet();
        for (int num : A) {
            if (num > 0) { // Greater than 0.
                numSet.add(num);
            }
        }
        // If not exists numbers, return 1.
        if (numSet.size() == 0) {
            return 1;
        }
        for (int idx = 1; idx <= Integer.MAX_VALUE; idx++) {
            if (!numSet.contains(idx)) {
                return idx;
            }
        }
        return 1;
    }
}

Code: 07:11:51 UTC, java, verify, result: Passed

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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

// 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");

import java.util.Set;
import java.util.HashSet;

class Solution {
    public int solution(int[] A) {
        Set<Integer> numSet = new HashSet();
        for (int num : A) {
            if (num > 0) { // Greater than 0.
                numSet.add(num);
            }
        }
        for (int idx = 1; idx <= Integer.MAX_VALUE; idx++) {
            if (!numSet.contains(idx)) {
                return idx;
            }
        }
        return 1;
    }
}

Analysis

expand all Example tests

▶

example1
first example test

✔

0.008 s

▶

example2
second example test

✔

0.008 s

▶

example3
third example test

✔

0.008 s

Code: 07:11:58 UTC, java, verify, result: Passed

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

// 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");

import java.util.Set;
import java.util.HashSet;

class Solution {
    public int solution(int[] A) {
        Set<Integer> numSet = new HashSet();
        for (int num : A) {
            if (num > 0) { // Greater than 0.
                numSet.add(num);
            }
        }
        for (int idx = 1; idx <= Integer.MAX_VALUE; idx++) {
            if (!numSet.contains(idx)) {
                return idx;
            }
        }
        return 1;
    }
}

Analysis

expand all Example tests

▶

example1
first example test

✔

0.012 s

▶

example2
second example test

✔

0.004 s

▶

example3
third example test

✔

0.004 s

Code: 07:12:04 UTC, java, 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

// 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");

import java.util.Set;
import java.util.HashSet;

class Solution {
    public int solution(int[] A) {
        Set<Integer> numSet = new HashSet();
        for (int num : A) {
            if (num > 0) { // Greater than 0.
                numSet.add(num);
            }
        }
        for (int idx = 1; idx <= Integer.MAX_VALUE; idx++) {
            if (!numSet.contains(idx)) {
                return idx;
            }
        }
        return 1;
    }
}

Analysis summary

The solution obtained perfect score.

Analysis

Detected time complexity:

O(N) or O(N * log(N))

expand all Example tests

▶

example1
first example test

✔

0.004 s

▶

example2
second example test

✔

0.004 s

▶

example3
third example test

✔

0.008 s

expand all Correctness tests

▶

extreme_single
a single element

✔

0.004 s

0.008 s

▶

simple
simple test

✔

0.004 s

▶

extreme_min_max_value
minimal and maximal values

✔

0.004 s

▶

positive_only
shuffled sequence of 0...100 and then 102...200

✔

0.004 s

▶

negative_only
shuffled sequence -100 ... -1

✔

0.004 s

expand all Performance tests

▶

medium
chaotic sequences length=10005 (with minus)

✔

0.032 s

0.024 s

0.040 s

▶

large_1
chaotic + sequence 1, 2, ..., 40000 (without minus)

✔

0.388 s

▶

large_2
shuffled sequence 1, 2, ..., 100000 (without minus)

✔

0.508 s

0.468 s

▶

large_3
chaotic + many -1, 1, 2, 3 (with minus)

✔

0.264 s