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 12 minutes

Notes

not defined yet

Code: 10:18:56 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: 10:19:02 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: 10:19:10 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")

def solution(A):
    sumL = A[0]
    sumR = sum(A[1:])
    mini = abs(sumR-sumL)
    
    for i in range(1,len(A)):
        sumL = sumL+A[i]
        sumR = sumR-A[i]
        diff = abs(sumR-sumL)
        if mini > diff:
            mini = diff
    
    return mini

Code: 10:19:17 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

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

def solution(A):
    sumL = A[0]
    sumR = sum(A[1:])
    mini = abs(sumR-sumL)
    
    for i in range(1,len(A)):
        sumL = sumL+A[i]
        sumR = sumR-A[i]
        diff = abs(sumR-sumL)
        if mini > diff:
            mini = diff
    
    return mini

User test case 1:

[0, 2000]

Analysis

expand all Example tests

▶

example
example test

✔

0.036 s

expand all User tests

▶

test_data1

✔

0.036 s

OK
function result: 2000

Code: 10:19:29 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

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

def solution(A):
    sumL = A[0]
    sumR = sum(A[1:])
    mini = abs(sumR-sumL)
    
    for i in range(1,len(A)):
        sumL = sumL+A[i]
        sumR = sumR-A[i]
        diff = abs(sumR-sumL)
        if mini > diff:
            mini = diff
    
    return mini

User test case 1:

[1000, 3000]

Analysis

expand all Example tests

▶

example
example test

✔

0.036 s

expand all User tests

▶

test_data1

✔

0.036 s

OK
function result: 2000

Code: 10:20:05 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

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

def solution(A):
    sumL = A[0]
    sumR = sum(A[1:])
    mini = abs(sumR-sumL)
    
    for i in range(1,len(A)):
        sumL = sumL+A[i]
        sumR = sumR-A[i]
        diff = abs(sumR-sumL)
        if mini > diff:
            mini = diff
    
    return mini

User test case 1:

[3000, 1000]

Analysis

expand all Example tests

▶

example
example test

✔

0.036 s

expand all User tests

▶

test_data1

✔

0.036 s

OK
function result: 2000

Code: 10:20:49 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

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

def solution(A):
    sumL = A[0]
    sumR = sum(A[1:])
    mini = abs(sumR-sumL)
    
    for i in range(1,len(A)):
        sumL = sumL+A[i]
        sumR = sumR-A[i]
        diff = abs(sumR-sumL)
        if mini > diff:
            mini = diff
    
    return mini

User test case 1:

[3000, 3000]

Analysis

expand all Example tests

▶

example
example test

✔

0.036 s

expand all User tests

▶

test_data1

✔

0.036 s

OK
function result: 0

Code: 10:21:04 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

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

def solution(A):
    sumL = A[0]
    sumR = sum(A[1:])
    mini = abs(sumR-sumL)
    
    for i in range(1,len(A)):
        sumL = sumL+A[i]
        sumR = sumR-A[i]
        diff = abs(sumR-sumL)
        if mini > diff:
            mini = diff
    
    return mini

User test case 1:

[3000, 3001]

Analysis

expand all Example tests

▶

example
example test

✔

0.048 s

expand all User tests

▶

test_data1

✔

0.048 s

OK
function result: 1

Code: 10:23:45 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")

def solution(A):
    sumL = A[0]
    sumR = sum(A[1:])
    mini = abs(sumR-sumL)
    
    for i in range(1,len(A)-):
        sumL = sumL+A[i]
        sumR = sumR-A[i]
        diff = abs(sumR-sumL)
        if mini > diff:
            mini = diff
    
    return mini

Code: 10:23:47 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

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

def solution(A):
    sumL = A[0]
    sumR = sum(A[1:])
    mini = abs(sumR-sumL)
    
    for i in range(1,len(A)-1):
        sumL = sumL+A[i]
        sumR = sumR-A[i]
        diff = abs(sumR-sumL)
        if mini > diff:
            mini = diff
    
    return mini

User test case 1:

[3002, 3001]

Analysis

expand all Example tests

▶

example
example test

✔

0.036 s

expand all User tests

▶

test_data1

✔

0.036 s

OK
function result: 1

Code: 10:25:08 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")

def solution(A):
    
    sumL = A[0]
    sumR = sum(A[1:])
    mini = abs(sumR-sumL)
    
    for i in range(1,len(A)-1):
        sumL = sumL+A[i]
        sumR = sumR-A[i]
        diff = abs(sumR-sumL)
        if mini > diff:
            mini = diff
    
    return mini

Code: 10:25:19 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")

def solution(A):
    n = len(A)
    sumL = A[0]
    sumR = sum(A[1:])
    mini = abs(sumR-sumL)
    
    for i in range(1,len(A)-1):
        sumL = sumL+A[i]
        sumR = sumR-A[i]
        diff = abs(sumR-sumL)
        if mini > diff:
            mini = diff
    
    return mini

Code: 10:29:51 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")

def solution(A):
    left = A[0]
    right = sum(A[1::])
    diff = abs(left - right)

    for p in range(1, len(A)):
        ldiff = abs(left - right)
        if ldiff < diff:
            diff = ldiff
        left += A[p]
        right -= A[p]

    return diff

Code: 10:29:58 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

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

def solution(A):
    left = A[0]
    right = sum(A[1::])
    diff = abs(left - right)

    for p in range(1, len(A)):
        ldiff = abs(left - right)
        if ldiff < diff:
            diff = ldiff
        left += A[p]
        right -= A[p]

    return diff

User test case 1:

[3002, 3001]

Analysis

expand all Example tests

▶

example
example test

✔

0.036 s

expand all User tests

▶

test_data1

✔

0.036 s

OK
function result: 1

Code: 10:30:00 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

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

def solution(A):
    left = A[0]
    right = sum(A[1::])
    diff = abs(left - right)

    for p in range(1, len(A)):
        ldiff = abs(left - right)
        if ldiff < diff:
            diff = ldiff
        left += A[p]
        right -= A[p]

    return 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

▶

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

✔

0.148 s

0.152 s

▶

large_random
random large, length = ~100,000

✔

0.160 s

0.168 s

▶

large_sequence
large sequence, length = ~100,000

✔

0.096 s

▶

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

✔

0.164 s

0.152 s

0.136 s