Test results - Codility

Tasks Details

easy

1. TapeEquilibrium

Minimize the value |(A[0] + ... + A[P-1]) - (A[P] + ... + A[N-1])|.

Task Score

100%

Correctness

100%

Performance

100%

A non-empty array A consisting of N integers is given. Array A represents numbers on a tape.

Any integer P, such that 0 < P < N, splits this tape into two non-empty parts: A[0], A[1], ..., A[P − 1] and A[P], A[P + 1], ..., A[N − 1].

The difference between the two parts is the value of: |(A[0] + A[1] + ... + A[P − 1]) − (A[P] + A[P + 1] + ... + A[N − 1])|

In other words, it is the absolute difference between the sum of the first part and the sum of the second part.

For example, consider array A such that:

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

We can split this tape in four places:

P = 1, difference = |3 − 10| = 7

P = 2, difference = |4 − 9| = 5

P = 3, difference = |6 − 7| = 1

P = 4, difference = |10 − 3| = 7

Write a function:

def solution(A)

that, given a non-empty array A of N integers, returns the minimal difference that can be achieved.

For example, given:

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

the function should return 1, as explained above.

Write an efficient algorithm for the following assumptions:

N is an integer within the range [2..100,000];

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

Solution

Programming language used Python

Time spent on task 5 minutes

Notes

not defined yet

Code: 11:23:04 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: 11:23:08 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: 11:23:12 UTC, py, autosave

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def solution(A):
    minimum = 100000
    current_sum = 0
    total = sum(A)
    
    for i in A[:-1]:
        current_sum += i
        rest = total - current_sum
        difference = abs(current_sum - rest)
        #print("%s: |%s - %s| = %s" % (i, current_sum, rest, difference))
        if difference < minimum:
            minimum = difference
    return minimum

Code: 11:23:35 UTC, py, autosave

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def solution(A):
    min_diff = 100000
    cur_sum = 0
    total = sum(A)
    
    for i in A[:-1]:
        current_sum += i
        rest = total - current_sum
        difference = abs(current_sum - rest)
        #print("%s: |%s - %s| = %s" % (i, current_sum, rest, difference))
        if difference < minimum:
            minimum = difference
    return minimum

Code: 11:23:47 UTC, py, autosave

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def solution(A):
    min_diff = 100000
    cur_sum = 0
    tot_sum = sum(A)
    
    for i in A[:-1]:
        cur_sum += i
        rest = total - current_sum
        difference = abs(current_sum - rest)
        #print("%s: |%s - %s| = %s" % (i, current_sum, rest, difference))
        if difference < minimum:
            minimum = difference
    return minimum

Code: 11:24:16 UTC, py, autosave

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def solution(A):
    minimum_diff = 100000
    current_sum = 0
    total_sum = sum(A)
    
    for i in A[:-1]:
        cur_sum += i
        second_part = total_sum - current_sum
        difference = abs(current_sum - rest)
        #print("%s: |%s - %s| = %s" % (i, current_sum, rest, difference))
        if difference < minimum:
            minimum = difference
    return minimum

Code: 11:24:27 UTC, py, autosave

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def solution(A):
    minimum_diff = 100000
    current_sum = 0
    total_sum = sum(A)
    
    for el in A[:-1]:
        current_sum += el
        second_part = total_sum - current_sum
        difference = abs(current_sum - rest)
        #print("%s: |%s - %s| = %s" % (i, current_sum, rest, difference))
        if difference < minimum:
            minimum = difference
    return minimum

Code: 11:24:45 UTC, py, autosave

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def solution(A):
    minimum_diff = 100000
    current_sum = 0
    total_sum = sum(A)
    
    for el in A[:-1]:
        current_sum += el
        second_part = total_sum - current_sum
        difference = abs(current_sum - second_part)
        #print("%s: |%s - %s| = %s" % (i, current_sum, rest, difference))
        if difference < minimum:
            minimum = difference
    return minimum

Code: 11:25:06 UTC, py, autosave

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def solution(A):
    total_sum = sum(A)
    minimum_diff = 100000
    first_sum = 0
    
    for el in A[:-1]:
        current_sum += el
        second_part = total_sum - current_sum
        difference = abs(current_sum - second_part)
        #print("%s: |%s - %s| = %s" % (i, current_sum, rest, difference))
        if difference < minimum:
            minimum = difference
    return minimum

Code: 11:25:16 UTC, py, autosave

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def solution(A):
    total_sum = sum(A)
    minimum_diff = 100000
    first_part = 0
    second_part = 0
    
    for el in A[:-1]:
        current_sum += el
        second_part = total_sum - current_sum
        difference = abs(current_sum - second_part)
        #print("%s: |%s - %s| = %s" % (i, current_sum, rest, difference))
        if difference < minimum:
            minimum = difference
    return minimum

Code: 11:25:28 UTC, py, autosave

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def solution(A):
    total_sum = sum(A)
    minimum_diff = 100000
    first_part = 0
    second_part = 0
    
    for el in A[:-1]:
        first_part += el
        second_part = total_sum - current_sum
        difference = abs(current_sum - second_part)
        #print("%s: |%s - %s| = %s" % (i, current_sum, rest, difference))
        if difference < minimum:
            minimum = difference
    return minimum

Code: 11:25:42 UTC, py, autosave

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def solution(A):
    total_sum = sum(A)
    minimum_diff = 100000
    first_part = 0
    second_part = 0
    
    for el in A[:-1]:
        first_part += el
        second_part = total_sum - first_part
        difference = abs(first_part - second_part)
        #print("%s: |%s - %s| = %s" % (i, current_sum, rest, difference))
        if difference < minimum:
            minimum = difference
    return minimum

Code: 11:25:49 UTC, py, verify, result: Passed

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def solution(A):
    total_sum = sum(A)
    minimum_diff = 100000
    first_part = 0
    second_part = 0
    
    for el in A[:-1]:
        first_part += el
        second_part = total_sum - first_part
        difference = abs(first_part - second_part)
        #print("%s: |%s - %s| = %s" % (i, current_sum, rest, difference))
        if difference < minimum_diff:
            minimum_diff = difference
    return minimum_diff

Analysis

expand all Example tests

▶

example
example test

✔

0.036 s

Code: 11:26:23 UTC, py, autosave

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def solution(A):
    total_sum = sum(A)
    minimum_diff = 100000
    first_part = 0
    second_part = 0
    
    for el in A[:-1]:
        first_part += el
        second_part = total_sum - first_part
        difference = abs(first_part - second_part)
        #print("|%s - %s| = %s" % (i, current_sum, rest, difference))
        if difference < minimum_diff:
            minimum_diff = difference
    return minimum_diff

Code: 11:26:36 UTC, py, autosave

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def solution(A):
    total_sum = sum(A)
    minimum_diff = 100000
    first_part = 0
    second_part = 0
    
    for el in A[:-1]:
        first_part += el
        second_part = total_sum - first_part
        difference = abs(first_part - second_part)
        #print("|%s - %s| = %s" % (i, first_part, rest, difference))
        if difference < minimum_diff:
            minimum_diff = difference
    return minimum_diff

Code: 11:26:44 UTC, py, autosave

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def solution(A):
    total_sum = sum(A)
    minimum_diff = 100000
    first_part = 0
    second_part = 0
    
    for el in A[:-1]:
        first_part += el
        second_part = total_sum - first_part
        difference = abs(first_part - second_part)
        #print("|%s - %s| = %s" % (first_part, second_part, difference))
        if difference < minimum_diff:
            minimum_diff = difference
    return minimum_diff

Code: 11:26:51 UTC, py, verify, result: Passed

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def solution(A):
    total_sum = sum(A)
    minimum_diff = 100000
    first_part = 0
    second_part = 0
    
    for el in A[:-1]:
        first_part += el
        second_part = total_sum - first_part
        difference = abs(first_part - second_part)
        print("|%s - %s| = %s" % (first_part, second_part, difference))
        if difference < minimum_diff:
            minimum_diff = difference
    return minimum_diff

Analysis

expand all Example tests

▶

example
example test

✔

0.036 s

stdout:

|3 - 10| = 7
|4 - 9| = 5
|6 - 7| = 1
|10 - 3| = 7

Code: 11:26:57 UTC, py, verify, result: Passed

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def solution(A):
    total_sum = sum(A)
    minimum_diff = 100000
    first_part = 0
    second_part = 0
    
    for el in A[:-1]:
        first_part += el
        second_part = total_sum - first_part
        difference = abs(first_part - second_part)
        #print("|%s - %s| = %s" % (first_part, second_part, difference))
        if difference < minimum_diff:
            minimum_diff = difference
    return minimum_diff

Analysis

expand all Example tests

▶

example
example test

✔

0.036 s

Code: 11:27:17 UTC, py, verify, result: Passed

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def solution(A):
    total_sum = sum(A)
    minimum_diff = 100000
    first_part = 0
    second_part = 0
    
    for el in A[:-1]:
        first_part += el
        second_part = total_sum - first_part
        difference = abs(first_part - second_part)
        #print("|%s - %s| = %s" % (first_part, second_part, difference))
        if difference < minimum_diff:
            minimum_diff = difference
    return minimum_diff

Analysis

expand all Example tests

▶

example
example test

✔

0.036 s

Code: 11:27:21 UTC, py, final, score: 100

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def solution(A):
    total_sum = sum(A)
    minimum_diff = 100000
    first_part = 0
    second_part = 0
    
    for el in A[:-1]:
        first_part += el
        second_part = total_sum - first_part
        difference = abs(first_part - second_part)
        #print("|%s - %s| = %s" % (first_part, second_part, difference))
        if difference < minimum_diff:
            minimum_diff = difference
    return minimum_diff

Analysis summary

The solution obtained perfect score.

Analysis

Detected time complexity:

O(N)

expand all Example tests

▶

example
example test

✔

0.036 s

expand all Correctness tests

▶

double
two elements

✔

0.036 s

▶

simple_positive
simple test with positive numbers, length = 5

✔

0.036 s

▶

simple_negative
simple test with negative numbers, length = 5

✔

0.036 s

▶

simple_boundary
only one element on one of the sides

✔

0.036 s

▶

small_random
random small, length = 100

✔

0.036 s

▶

small_range
range sequence, length = ~1,000

✔

0.036 s

▶

small
small elements

✔

0.036 s

expand all Performance tests

▶

medium_random1
random medium, numbers from 0 to 100, length = ~10,000

✔

0.048 s

▶

medium_random2
random medium, numbers from -1,000 to 50, length = ~10,000

✔

0.048 s

▶

large_ones
large sequence, numbers from -1 to 1, length = ~100,000

✔

0.152 s

0.144 s

▶

large_random
random large, length = ~100,000

✔

0.160 s

0.164 s

▶

large_sequence
large sequence, length = ~100,000

✔

0.096 s

▶

large_extreme
large test with maximal and minimal values, length = ~100,000

✔

0.160 s

0.152 s

0.136 s