Test results - Codility

Tasks Details

easy

1. FirstUnique

Find the first unique number in a given sequence.

Task Score

100%

Correctness

100%

Performance

100%

A non-empty array A consisting of N integers is given. The unique number is the number that occurs exactly once in array A.

For example, the following array A:

A[0] = 4 A[1] = 10 A[2] = 5 A[3] = 4 A[4] = 2 A[5] = 10

contains two unique numbers (5 and 2).

You should find the first unique number in A. In other words, find the unique number with the lowest position in A.

For above example, 5 is in second position (because A[2] = 5) and 2 is in fourth position (because A[4] = 2). So, the first unique number is 5.

Write a function:

def solution(A)

that, given a non-empty array A of N integers, returns the first unique number in A. The function should return −1 if there are no unique numbers in A.

For example, given:

A[0] = 1 A[1] = 4 A[2] = 3 A[3] = 3 A[4] = 1 A[5] = 2

the function should return 4. There are two unique numbers (4 and 2 occur exactly once). The first one is 4 in position 1 and the second one is 2 in position 5. The function should return 4 bacause it is unique number with the lowest position.

Given array A such that:

A[0] = 6 A[1] = 4 A[2] = 4 A[3] = 6

the function should return −1. There is no unique number in A (4 and 6 occur more than once).

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 [0..1,000,000,000].

Solution

Programming language used Python

Time spent on task 33 minutes

Notes

not defined yet

Task timeline

Code: 14:00:27 UTC, java, autosave

show code in pop-up

1 2 3 4 5 6 7 8 9 10 11

// 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: 14:00:34 UTC, py, autosave

show code in pop-up

1 2 3 4 5 6

# 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: 14:00:39 UTC, vb, autosave

show code in pop-up

1 2 3 4 5 6

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

Private Function solution(A As Integer()) As Integer
    ' write your code in VB.NET 4.0 (Mono)
End Function

Code: 14:00:50 UTC, py, autosave

show code in pop-up

1 2 3 4 5 6

# 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: 14:19:19 UTC, py, autosave

show code in pop-up

1 2 3 4 5 6

# 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: 14:26:23 UTC, py, autosave

show code in pop-up

1 2 3 4 5 6

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

def solution(A):

Code: 14:26:54 UTC, py, autosave

show code in pop-up

1 2 3 4 5 6 7 8

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

om

def solution(A):

Code: 14:27:10 UTC, py, autosave

show code in pop-up

1 2 3 4 5 6 7 8

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

from collections import defaultdict

def solution(A):

Code: 14:27:21 UTC, py, autosave

show code in pop-up

1 2 3 4 5 6 7 8

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

from collections import defaultdict

def solution(A):
    
    dic = defaultdict()

Code: 14:27:32 UTC, py, autosave

show code in pop-up

1 2 3 4 5 6 7 8 9 10

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

from collections import defaultdict

def solution(A):
    
    dic = defaultdict(int)

    for

Code: 14:27:43 UTC, py, autosave

show code in pop-up

1 2 3 4 5 6 7 8 9 10

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

from collections import defaultdict

def solution(A):
    
    dic = defaultdict(int)

    for A

Code: 14:28:07 UTC, py, autosave

show code in pop-up

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

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

from collections import defaultdict

def solution(A):
    
    dic = defaultdict(int)

    for a in A:
        dic[a] += 1

Code: 14:29:39 UTC, py, autosave

show code in pop-up

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

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

from collections import defaultdict

def solution(A):
    
    dic = defaultdict(int)

    for a in A:
        dic[a] += 1

    p

Code: 14:29:43 UTC, py, verify, result: Failed

show code in pop-up

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

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

from collections import defaultdict

def solution(A):
    
    dic = defaultdict(int)

    for a in A:
        dic[a] += 1

    print(dic)

Analysis

expand all Example tests

▶

example0
example

✘

RUNTIME ERROR
tested program terminated with exit code 1

0.036 s

RUNTIME ERROR, tested program terminated with exit code 1

stderr:

Invalid result type, int expected, <class 'NoneType'> found.

stdout:

defaultdict(<class 'int'>, {4: 2, 10: 2, 5: 1, 2: 1})

▶

example1
example

✘

RUNTIME ERROR
tested program terminated with exit code 1

0.036 s

RUNTIME ERROR, tested program terminated with exit code 1

stderr:

Invalid result type, int expected, <class 'NoneType'> found.

stdout:

defaultdict(<class 'int'>, {1: 2, 4: 1, 3: 2, 2: 1})

▶

example2
example

✘

RUNTIME ERROR
tested program terminated with exit code 1

0.036 s

RUNTIME ERROR, tested program terminated with exit code 1

stderr:

Invalid result type, int expected, <class 'NoneType'> found.

stdout:

defaultdict(<class 'int'>, {6: 2, 4: 2})

Code: 14:30:46 UTC, py, autosave

show code in pop-up

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

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

from collections import defaultdict

def solution(A):
    
    dic = defaultdict(int)

    for a in A:
        dic[a] += 1

    

    print(dic)

Code: 14:30:58 UTC, py, autosave

show code in pop-up

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

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

from collections import defaultdict

def solution(A):
    
    dic = defaultdict(int)

    for a in A:
        dic[a] += 1

    for k,v in 

    print(dic)

Code: 14:31:23 UTC, py, autosave

show code in pop-up

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

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

from collections import defaultdict

def solution(A):
    
    dic = defaultdict(int)

    for a in A:
        dic[a] += 1

    for k,v in dic.items:
        

    print(dic)

Code: 14:31:53 UTC, py, autosave

show code in pop-up

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

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

from collections import defaultdict

def solution(A):
    
    dic = defaultdict(int)

    for a in A:
        dic[a] += 1

    for k,v in dic.items:
        if 

    print(dic)

Code: 14:32:07 UTC, py, autosave

show code in pop-up

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

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

from collections import defaultdict

def solution(A):
    
    dic = defaultdict(int)

    for a in A:
        dic[a] += 1

    for k,v in dic.items:
        if v == 1:
            return k
    
    return -1

Code: 14:32:08 UTC, py, verify, result: Failed

show code in pop-up

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

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

from collections import defaultdict

def solution(A):
    
    dic = defaultdict(int)

    for a in A:
        dic[a] += 1

    for k,v in dic.items:
        if v == 1:
            return k
    
    return -1

Analysis

expand all Example tests

▶

example0
example

✘

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 13, in solution
    for k,v in dic.items:
TypeError: 'builtin_function_or_method' object is not iterable

▶

example1
example

✘

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 13, in solution
    for k,v in dic.items:
TypeError: 'builtin_function_or_method' object is not iterable

▶

example2
example

✘

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 13, in solution
    for k,v in dic.items:
TypeError: 'builtin_function_or_method' object is not iterable

Code: 14:32:20 UTC, py, 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

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

from collections import defaultdict

def solution(A):
    
    dic = defaultdict(int)

    for a in A:
        dic[a] += 1

    for k,v in dic.items():
        if v == 1:
            return k
    
    return -1

Analysis

expand all Example tests

▶

example0
example

✔

0.036 s

▶

example1
example

✔

0.036 s

▶

example2
example

✔

0.036 s

Code: 14:32:32 UTC, py, 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

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

from collections import defaultdict

def solution(A):
    
    dic = defaultdict(int)

    for a in A:
        dic[a] += 1

    for k,v in dic.items():
        if v == 1:
            return k
    
    return -1

Analysis

expand all Example tests

▶

example0
example

✔

0.036 s

▶

example1
example

✔

0.036 s

▶

example2
example

✔

0.036 s

Code: 14:32:34 UTC, py, 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

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

from collections import defaultdict

def solution(A):
    
    dic = defaultdict(int)

    for a in A:
        dic[a] += 1

    for k,v in dic.items():
        if v == 1:
            return k
    
    return -1

Analysis summary

The solution obtained perfect score.

Analysis

Detected time complexity:

O(N * log(N))

expand all Example tests

▶

example0
example

✔

0.036 s

▶

example1
example

✔

0.036 s

▶

example2
example

✔

0.036 s

expand all Correctness tests

▶

extreme_single
single element

✔

0.036 s

▶

extreme_no_unique
no unique value and [1,2,3,4]

✔

0.036 s

▶

extreme_min_max_value
min/max values

✔

0.036 s

▶

small1
small correctness test

✔

0.036 s

▶

small2
small correctness test

✔

0.036 s

▶

small3
small correctness tests

✔

0.036 s

expand all Performance tests

▶

medium1
medium tests with few unique values, N = 10,003,

✔

0.048 s

▶

medium2
medium tests with few unique values, N = 10,209,

✔

0.048 s

▶

large
large tests with many minimal and maximal values, N = 50,000

✔

0.088 s

0.100 s

▶

big1
large test, N = 100,000

✔

0.152 s

▶

big2
large test, N = 100,000

✔

0.156 s