Task description:
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] = 3
The 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
class Solution { public int solution(int[] 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.
Assume that:
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].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] = 3
the function may return 0, 2, 4, 6 or 7, as explained above.
Complexity:
expected worst-case time complexity is O(N);expected worst-case space complexity is O(1), beyond input storage (not counting the storage required for input arguments).Solution:
返回一个列表中出现次数超过列表长度一半的字符的下标：
def solution(p): lenthp = len(p) setp = set(p) d = {} for i in setp: d[i]=p.count(i) maxv = max(d.values()) maxkey = max(d, key=d.get) #找出字典中值最大的键 if maxv > lenthp/2: return p.index(maxkey) else : return -1
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