Test results - Codility

Tasks Details

easy

1. Dominator

Find an index of an array such that its value occurs at more than half of indices in the array.

Task Score

100%

Correctness

100%

Performance

100%

对于一个给定的整数数组, "支配者"是在这个数组中出现的频率超过一半的整数.

例如:

A[0] = 3 A[1] = 4 A[2] = 3 A[3] = 2 A[4] = 3 A[5] = -1 A[6] = 3 A[7] = 3

数值"3"出现过5次, 5/8 > 0.5, 所以数值"3"是一个"支配者";

而在这个数组中, 这个"支配者"出现在数组下标:

0, 2, 4, 6 , 7.

请写一个函数

def solution(A)

对给定数组返回其任意一个支配者的数组下标。

例如，对上述数组，函数可以返回0，2，4，6，7中的任意一个。如果没有支配者，函数应该返回 −1。

假定:

N 是 [0..100,000] 内的整数;

数组 A 每个元素是取值范围 [−2,147,483,648..2,147,483,647] 内的整数 .

Solution

Programming language used Python

Time spent on task 4 minutes

Notes

not defined yet

Code: 08:00:20 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: 08:00:24 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: 08:00:27 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: 08:00:35 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

Code: 08:00:58 UTC, py, autosave

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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
    dominator = [0,

Code: 08:01:20 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
    if A == []:
        return -1
    dominator = [0, A[0], 1]
    for

Code: 08:01:50 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
    if A == []:
        return -1
    dominator = [0, A[0], 1]
    for i in range(1, len(A)):
        if A[i] == dominator[1]:
            dominator[2] += 1
        el

Code: 08:02:04 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
    if A == []:
        return -1
    dominator = [0, A[0], 1]
    for i in range(1, len(A)):
        if A[i] == dominator[1]:
            dominator[2] += 1
        elif dominator[2] == 0:

Code: 08:02:34 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
    if A == []:
        return -1
    dominator = [0, A[0], 1]
    for i in range(1, len(A)):
        if A[i] == dominator[1]:
            dominator[2] += 1
        elif dominator[2] == 0:
            dominator[1] = A[i]
            dominator[2] = 1
            dominator[0] = i
        else:
            dominator[2]

Code: 08:02:48 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
    if A == []:
        return -1
    dominator = [0, A[0], 1]
    for i in range(1, len(A)):
        if A[i] == dominator[1]:
            dominator[2] += 1
        elif dominator[2] == 0:
            dominator[1] = A[i]
            dominator[2] = 1
            dominator[0] = i
        else:
            dominator[2] -= 1
    return dominator[0]

Code: 08:02:49 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):
    # write your code in Python 3.6
    if A == []:
        return -1
    dominator = [0, A[0], 1]
    for i in range(1, len(A)):
        if A[i] == dominator[1]:
            dominator[2] += 1
        elif dominator[2] == 0:
            dominator[1] = A[i]
            dominator[2] = 1
            dominator[0] = i
        else:
            dominator[2] -= 1
    return dominator[0]

Analysis

expand all Example tests

▶

example
example test

✔

0.036 s

Code: 08:03:19 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
    if A == []:
        return -1
    dominator = [0, A[0], 1]
    for i in range(1, len(A)):
        if A[i] == dominator[1]:
            dominator[2] += 1
        elif dominator[2] == 0:
            dominator[1] = A[i]
            dominator[2] = 1
            dominator[0] = i
        else:
            dominator[2] -= 1
    if A.count(dominator[1]) <
    return dominator[0]

Code: 08:03:33 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
    if A == []:
        return -1
    dominator = [0, A[0], 1]
    for i in range(1, len(A)):
        if A[i] == dominator[1]:
            dominator[2] += 1
        elif dominator[2] == 0:
            dominator[1] = A[i]
            dominator[2] = 1
            dominator[0] = i
        else:
            dominator[2] -= 1
    if A.count(dominator[1]) <= len(A) / 2:
        return -1
    return dominator[0]

Code: 08:03:40 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):
    # write your code in Python 3.6
    if A == []:
        return -1
    dominator = [0, A[0], 1]
    for i in range(1, len(A)):
        if A[i] == dominator[1]:
            dominator[2] += 1
        elif dominator[2] == 0:
            dominator[1] = A[i]
            dominator[2] = 1
            dominator[0] = i
        else:
            dominator[2] -= 1
    if A.count(dominator[1]) <= len(A) / 2:
        return -1
    return dominator[0]

Analysis

expand all Example tests

▶

example
example test

✔

0.036 s

expand all User tests

▶

test_data1

✔

0.036 s

OK
function result: -1

User test case 1:

[3, 1, 2, 3, 4]

Code: 08:03:49 UTC, py, verify, result: Passed

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):
    # write your code in Python 3.6
    if A == []:
        return -1
    dominator = [0, A[0], 1]
    for i in range(1, len(A)):
        if A[i] == dominator[1]:
            dominator[2] += 1
        elif dominator[2] == 0:
            dominator[1] = A[i]
            dominator[2] = 1
            dominator[0] = i
        else:
            dominator[2] -= 1
    if A.count(dominator[1]) <= len(A) / 2:
        return -1
    return dominator[0]

Analysis

expand all Example tests

▶

example
example test

✔

0.036 s

expand all User tests

▶

test_data1

✔

0.036 s

OK
function result: -1

User test case 1:

[3, 1, 2, 3, 4]

Code: 08:03:51 UTC, py, final, score: 100

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):
    # write your code in Python 3.6
    if A == []:
        return -1
    dominator = [0, A[0], 1]
    for i in range(1, len(A)):
        if A[i] == dominator[1]:
            dominator[2] += 1
        elif dominator[2] == 0:
            dominator[1] = A[i]
            dominator[2] = 1
            dominator[0] = i
        else:
            dominator[2] -= 1
    if A.count(dominator[1]) <= len(A) / 2:
        return -1
    return dominator[0]

Analysis summary

The solution obtained perfect score.

Analysis

Detected time complexity:

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

expand all Example tests

▶

example
example test

✔

0.036 s

expand all Correctness tests

▶

small_nondominator
all different and all the same elements

✔

0.036 s

▶

small_half_positions
half elements the same, and half + 1 elements the same

✔

0.036 s

▶

small
small test

✔

0.036 s

▶

small_pyramid
decreasing and plateau, small

✔

0.036 s

▶

extreme_empty_and_single_item
empty and single element arrays

✔

0.036 s

▶

extreme_half1
array with exactly N/2 values 1, N even + [0,0,1,1,1]

✔

0.036 s

▶

extreme_half2
array with exactly floor(N/2) values 1, N odd + [0,0,1,1,1]

✔

0.036 s

▶

extreme_half3
array with exactly ceil(N/2) values 1 + [0,0,1,1,1]

✔

0.036 s

expand all Performance tests

▶

medium_pyramid
decreasing and plateau, medium

✔

0.048 s

▶

large_pyramid
decreasing and plateau, large

✔

0.156 s

▶

medium_random
random test with dominator, N = 10,000

✔

0.076 s

▶

large_random
random test with dominator, N = 100,000

✔

0.152 s