Test results - Codility

Tasks Details

easy

1. PermMissingElem

Find the missing element in a given permutation.

Task Score

100%

Correctness

100%

Performance

100%

An array A consisting of N different integers is given. The array contains integers in the range [1..(N + 1)], which means that exactly one element is missing.

Your goal is to find that missing element.

Write a function:

def solution(A)

that, given an array A, returns the value of the missing element.

For example, given array A such that:

A[0] = 2 A[1] = 3 A[2] = 1 A[3] = 5

the function should return 4, as it is the missing element.

Write an efficient algorithm for the following assumptions:

N is an integer within the range [0..100,000];

the elements of A are all distinct;

each element of array A is an integer within the range [1..(N + 1)].

Solution

Programming language used Python

Time spent on task 6 minutes

Notes

not defined yet

Code: 09:35:51 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");

class Solution {
    public int solution(int[] A) {
        // write your code in Java SE 8
    }
}

Code: 09:36:59 UTC, py, autosave

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

def solution(A):
    # write your code in Python 3.6
    pass

Code: 09:37:12 UTC, py, autosave

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

def solution(A):
    check_list = [False]

Code: 09:37:32 UTC, py, autosave

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

def solution(A):
    check_list = [False] * len(A)

Code: 09:38:03 UTC, py, autosave

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

def solution(A):
    check_list = [False] * len(A)
    
    for i in A:
        check_list[i-1] = True
    
    for j in check_list:
        if j:

Code: 09:38:17 UTC, py, verify, result: Failed

show code in pop-up

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

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

def solution(A):
    check_list = [False] * len(A)
    
    for i in A:
        check_list[i-1] = True
    
    for j in check_list:
        if not j:
            return j + 1

Analysis

expand all Example tests

▶

example
example test

✘

RUNTIME ERROR
tested program terminated with exit code 1

0.036 s

RUNTIME ERROR, tested program terminated with exit code 1

stderr:

Traceback (most recent call last):
  File "exec.py", line 129, in <module>
    main()
  File "exec.py", line 91, in main
    result = solution( A )
  File "/tmp/solution.py", line 8, in solution
    check_list[i-1] = True
IndexError: list assignment index out of range

Code: 09:39:15 UTC, py, autosave

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

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

def solution(A):
    check_list = [False] * len(A) 
    
    for i in A:
        check_list[i-1] = True
    
    for j in check_list:
        if not j:
            return j + 1

Code: 09:39:18 UTC, py, verify, result: Failed

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

def solution(A):
    check_list = [False] * len(A) + 1
    
    for i in A:
        check_list[i-1] = True
    
    for j in check_list:
        if not j:
            return j + 1

Analysis

expand all Example tests

▶

example
example test

✘

RUNTIME ERROR
tested program terminated with exit code 1

0.036 s

RUNTIME ERROR, tested program terminated with exit code 1

stderr:

Traceback (most recent call last):
  File "exec.py", line 129, in <module>
    main()
  File "exec.py", line 91, in main
    result = solution( A )
  File "/tmp/solution.py", line 5, in solution
    check_list = [False] * len(A) + 1
TypeError: can only concatenate list (not "int") to list

Code: 09:39:22 UTC, py, verify, result: Failed

show code in pop-up

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

def solution(A):
    check_list = [False] * (len(A) + 1)
    
    for i in A:
        check_list[i-1] = True
    
    for j in check_list:
        if not j:
            return j + 1

Analysis

expand all Example tests

▶

example
example test

✘

WRONG ANSWER
got 1 expected 4

0.036 s

WRONG ANSWER, got 1 expected 4

Code: 09:40:38 UTC, py, autosave

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

def solution(A):
    check_list = [False] * (len(A) + 1)
    
    for i in A:
        check_list[i-1] = True
        
        
    
    for j in check_list:
        if not j:
            return j + 1

Code: 09:40:43 UTC, py, verify, result: Failed

show code in pop-up

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

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

def solution(A):
    check_list = [False] * (len(A) + 1)
    
    for i in A:
        check_list[i-1] = True
        
    print(check_list)
    
    for j in check_list:
        if not j:
            return j + 1

Analysis

expand all Example tests

▶

example
example test

✘

WRONG ANSWER
got 1 expected 4

0.036 s

WRONG ANSWER, got 1 expected 4

stdout:

[True, True, True, False, True]

Code: 09:41:06 UTC, py, verify, result: Passed

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

def solution(A):
    check_list = [False] * (len(A) + 1)
    
    for i in A:
        check_list[i-1] = True
        
    print(check_list)
    
    for idx, j in enumerate(check_list):
        if not j:
            return idx + 1

Analysis

expand all Example tests

▶

example
example test

✔

0.036 s

stdout:

[True, True, True, False, True]

Code: 09:41:10 UTC, py, autosave

show code in pop-up

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

def solution(A):
    check_list = [False] * (len(A) + 1)
    
    for i in A:
        check_list[i-1] = True
        
    
    
    for idx, j in enumerate(check_list):
        if not j:
            return idx + 1

Code: 09:41:14 UTC, py, verify, result: Passed

show code in pop-up

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

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

def solution(A):
    check_list = [False] * (len(A) + 1)
    
    for i in A:
        check_list[i-1] = True
    
    for idx, j in enumerate(check_list):
        if not j:
            return idx + 1

Analysis

expand all Example tests

▶

example
example test

✔

0.036 s

Code: 09:41:17 UTC, py, verify, result: Passed

show code in pop-up

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

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

def solution(A):
    check_list = [False] * (len(A) + 1)
    
    for i in A:
        check_list[i-1] = True
    
    for idx, j in enumerate(check_list):
        if not j:
            return idx + 1

Analysis

expand all Example tests

▶

example
example test

✔

0.036 s

Code: 09:41:19 UTC, py, final, score: 100

show code in pop-up

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

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

def solution(A):
    check_list = [False] * (len(A) + 1)
    
    for i in A:
        check_list[i-1] = True
    
    for idx, j in enumerate(check_list):
        if not j:
            return idx + 1

Analysis summary

The solution obtained perfect score.

Analysis

Detected time complexity:

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

expand all Example tests

▶

example
example test

✔

0.036 s

expand all Correctness tests

▶

empty_and_single
empty list and single element

✔

0.036 s

▶

missing_first_or_last
the first or the last element is missing

✔

0.036 s

▶

single
single element

✔

0.036 s

▶

double
two elements

✔

0.036 s

▶

simple
simple test

✔

0.036 s

expand all Performance tests

▶

medium1
medium test, length = ~10,000

✔

0.044 s

▶

medium2
medium test, length = ~10,000

✔

0.044 s

▶

large_range
range sequence, length = ~100,000

✔

0.136 s

0.084 s

0.088 s

▶

large1
large test, length = ~100,000

✔

0.136 s

▶

large2
large test, length = ~100,000

✔

0.100 s