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:

int solution(int A[], int N);

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 C

Time spent on task 2 minutes

Notes

not defined yet

Task timeline

Code: 03:09:43 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: 03:09:45 UTC, c, autosave

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

int solution(int A[], int N) {
    // write your code in C99 (gcc 6.2.0)
}

Code: 03:10:05 UTC, c, autosave

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

int solution(int A[], int N) {
    // write your code in C99 (gcc 6.2.0)
    int i, sum = 0, max = 0;
    int arr[1000001];
    
    for(i = 0; i &lt; N; i++){
        if(0 &gt; A[i]) continue;
        
        if(arr[A[i]] != A[i]){
            sum += A[i];
            arr[A[i]] = A[i];
            if(max &lt; A[i]) max = A[i];
        }
    }
    if(max == 0)
        return 1;

    for(i = 1; i &lt;= max; i++){
        if(arr[i] != i)
            return i;
    }
 
    return max + 1;
}

Code: 03:10:15 UTC, c, autosave

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

int solution(int A[], int N) {
    // write your code in C99 (gcc 6.2.0)
    int i, max = 0;
    int arr[1000001];
    
    for(i = 0; i &lt; N; i++){
        if(0 &gt; A[i]) continue;
        
        if(arr[A[i]] != A[i]){
            arr[A[i]] = A[i];
            if(max &lt; A[i]) max = A[i];
        }
    }
    if(max == 0)
        return 1;

    for(i = 1; i &lt;= max; i++){
        if(arr[i] != i)
            return i;
    }
 
    return max + 1;
}

Code: 03:10:25 UTC, c, autosave

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

int solution(int A[], int N) {
    // write your code in C99 (gcc 6.2.0)
    int i, max = 0;
    int arr[1000001];
    
    for(i = 0; i &lt; N; i++){
        if(0 < A[i]) continue;
        
        if(arr[A[i]] != A[i]){
            arr[A[i]] = A[i];
            if(max &lt; A[i]) max = A[i];
        }
    }
    if(max == 0)
        return 1;

    for(i = 1; i &lt;= max; i++){
        if(arr[i] != i)
            return i;
    }
 
    return max + 1;
}

Code: 03:10:36 UTC, c, autosave

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

int solution(int A[], int N) {
    // write your code in C99 (gcc 6.2.0)
    int i, max = 0;
    int arr[1000001];
    
    for(i = 0; i &lt; N; i++){
        if(0 > A[i]) continue;
        
        if(arr[A[i]] != A[i]){
            arr[A[i]] = A[i];
            if(max &lt; A[i]) max = A[i];
        }
    }
    if(max == 0)
        return 1;

    for(i = 1; i &lt;= max; i++){
        if(arr[i] != i)
            return i;
    }
 
    return max + 1;
}

Code: 03:10:46 UTC, c, autosave

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

int solution(int A[], int N) {
    // write your code in C99 (gcc 6.2.0)
    int i, max = 0;
    int arr[1000001];
    
    for(i = 0; i &lt; N; i++){
        if(0 > A[i]) continue;
        
        if(arr[A[i]] != A[i]){
            arr[A[i]] = A[i];
            if(max < A[i]) max = A[i];
        }
    }
    if(max == 0)
        return 1;

    for(i = 1; i &lt;= max; i++){
        if(arr[i] != i)
            return i;
    }
 
    return max + 1;
}

Code: 03:10:49 UTC, c, verify, result: Failed

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

int solution(int A[], int N) {
    // write your code in C99 (gcc 6.2.0)
    int i, max = 0;
    int arr[1000001];
    
    for(i = 0; i &lt; N; i++){
        if(0 > A[i]) continue;
        
        if(arr[A[i]] != A[i]){
            arr[A[i]] = A[i];
            if(max < A[i]) max = A[i];
        }
    }
    if(max == 0)
        return 1;

    for(i = 1; i <= max; i++){
        if(arr[i] != i)
            return i;
    }
 
    return max + 1;
}

Analysis

Compile error

func.c: In function 'solution':
func.c:9:19: error: 'lt' undeclared (first use in this function)
     for(i = 0; i &lt; N; i++){
                   ^~
func.c:9:19: note: each undeclared identifier is reported only once for each function it appears in
func.c:9:5: warning: statement with no effect [-Wunused-value]
     for(i = 0; i &lt; N; i++){
     ^~~
func.c:9:24: error: expected ')' before ';' token
     for(i = 0; i &lt; N; i++){
                        ^

Code: 03:10:59 UTC, c, autosave

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

int solution(int A[], int N) {
    // write your code in C99 (gcc 6.2.0)
    int i, max = 0;
    int arr[1000001];
    
    for(i = 0; i < N; i++){
        if(0 > A[i]) continue;
        
        if(arr[A[i]] != A[i]){
            arr[A[i]] = A[i];
            if(max < A[i]) max = A[i];
        }
    }
    if(max == 0)
        return 1;

    for(i = 1; i <= max; i++){
        if(arr[i] != i)
            return i;
    }
 
    return max + 1;
}

Code: 03:11:02 UTC, c, verify, result: Passed

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

int solution(int A[], int N) {
    // write your code in C99 (gcc 6.2.0)
    int i, max = 0;
    int arr[1000001];
    
    for(i = 0; i < N; i++){
        if(0 > A[i]) continue;
        
        if(arr[A[i]] != A[i]){
            arr[A[i]] = A[i];
            if(max < A[i]) max = A[i];
        }
    }
    if(max == 0)
        return 1;

    for(i = 1; i <= max; i++){
        if(arr[i] != i)
            return i;
    }
 
    return max + 1;
}

Analysis

expand all Example tests

▶

example1
first example test

✔

0.001 s

▶

example2
second example test

✔

0.001 s

▶

example3
third example test

✔

0.001 s

Code: 03:11:12 UTC, c, verify, result: Passed

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

int solution(int A[], int N) {
    // write your code in C99 (gcc 6.2.0)
    int i, max = 0;
    int arr[1000001];
    
    for(i = 0; i < N; i++){
        if(0 > A[i]) continue;
        
        if(arr[A[i]] != A[i]){
            arr[A[i]] = A[i];
            if(max < A[i]) max = A[i];
        }
    }
    if(max == 0)
        return 1;

    for(i = 1; i <= max; i++){
        if(arr[i] != i)
            return i;
    }
 
    return max + 1;
}

Analysis

expand all Example tests

▶

example1
first example test

✔

0.001 s

▶

example2
second example test

✔

0.001 s

▶

example3
third example test

✔

0.001 s

Code: 03:11:14 UTC, c, final, score: 100

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

int solution(int A[], int N) {
    // write your code in C99 (gcc 6.2.0)
    int i, max = 0;
    int arr[1000001];
    
    for(i = 0; i < N; i++){
        if(0 > A[i]) continue;
        
        if(arr[A[i]] != A[i]){
            arr[A[i]] = A[i];
            if(max < A[i]) max = A[i];
        }
    }
    if(max == 0)
        return 1;

    for(i = 1; i <= max; i++){
        if(arr[i] != i)
            return i;
    }
 
    return max + 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

✔

0.001 s

▶

example2
second example test

✔

0.001 s

▶

example3
third example test

✔

0.001 s

expand all Correctness tests

▶

extreme_single
a single element

✔

0.001 s

▶

simple
simple test

✔

0.001 s

▶

extreme_min_max_value
minimal and maximal values

✔

0.001 s

▶

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

✔

0.001 s

▶

negative_only
shuffled sequence -100 ... -1

✔

0.001 s

expand all Performance tests

▶

medium
chaotic sequences length=10005 (with minus)

✔

0.001 s

0.004 s

▶

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

✔

0.008 s

▶

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

✔

0.008 s

▶

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

✔

0.008 s