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%
An array A consisting of N integers is given. The dominator of array A is the value that occurs in more than half of the elements of A.
For example, consider array A such that
A[0] = 3 A[1] = 4 A[2] = 3 A[3] = 2 A[4] = 3 A[5] = -1 A[6] = 3 A[7] = 3The dominator of A is 3 because it occurs in 5 out of 8 elements of A (namely in those with indices 0, 2, 4, 6 and 7) and 5 is more than a half of 8.
Write a function
def solution(A)
that, given an array A consisting of N integers, returns index of any element of array A in which the dominator of A occurs. The function should return −1 if array A does not have a dominator.
For example, given array A such that
A[0] = 3 A[1] = 4 A[2] = 3 A[3] = 2 A[4] = 3 A[5] = -1 A[6] = 3 A[7] = 3the function may return 0, 2, 4, 6 or 7, as explained above.
Write an efficient algorithm for the following assumptions:
- N is an integer within the range [0..100,000];
- each element of array A is an integer within the range [−2,147,483,648..2,147,483,647].
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Solution
Programming language used Python
Total time used 3 minutes
Effective time used 3 minutes
Notes
not defined yet
Task timeline
Code: 10:00:24 UTC,
java,
autosave
Code: 10:01:50 UTC,
py,
verify,
result: Passed
from typing import List
from collections import Counter
def solution(A: List) -> int:
if len(A):
element, count = Counter(A).most_common(1)[0]
if count > len(A)/2:
return A.index(element)
return -1
User test case 1:
[0, 0, 0, 0, 1, 1, 1, 1, 1]
User test case 2:
[1, 1, 2, 3, 4, 5]
Analysis
Code: 10:02:27 UTC,
py,
verify,
result: Passed
from typing import List
from collections import Counter
def solution(A: List) -> int:
if len(A):
element, count = Counter(A).most_common(1)[0]
if count > len(A)/2:
return A.index(element)
return -1
User test case 1:
[0, 0, 0, 0, 1, 1, 1, 1, 1]
User test case 2:
[1, 1, 2, 3, 4, 5]
Analysis
Code: 10:02:30 UTC,
py,
final,
score: 
100
Analysis summary
The solution obtained perfect score.
Analysis
Detected time complexity:
O(N*log(N)) or O(N)
expand all
Correctness tests
1.
0.052 s
OK
2.
0.052 s
OK
1.
0.052 s
OK
2.
0.052 s
OK
1.
0.052 s
OK
2.
0.056 s
OK
1.
0.056 s
OK
1.
0.052 s
OK
2.
0.052 s
OK
1.
0.056 s
OK
2.
0.052 s
OK
1.
0.052 s
OK
2.
0.052 s
OK
1.
0.052 s
OK
2.
0.056 s
OK