360ship面试题

By | 2014/07/18

A zero-indexed array A consisting of N integers is given. An equilibrium index of this array is any integer P such that 0 ≤ P < N and the sum of elements of lower indices is equal to the sum of elements of higher indices, i.e.

A + A + … + A[P−1] = A[P+1] + … + A[N−2] + A[N−1].

Sum of zero elements is assumed to be equal to 0. This can happen if P = 0 or if P = N−1.
For example, consider the following array A consisting of N = 7 elements:

A = -7 A = 1 A = 5A = 2 A = -4 A = 3A = 0
P = 3 is an equilibrium index of this array, because:

* A + A + A = A + A + A

P = 6 is also an equilibrium index, because:

* A + A + A + A + A + A = 0

and there are no elements with indices greater than 6.
P = 7 is not an equilibrium index, because it does not fulfill the condition 0 ≤ P len(A)/2不成立，所以返回-1，如果A = [2，2，2，2，2，3，4，5，6]，
num(2)>len(A)/2成立，所以返回2，代码如下：
[code lang=”python”]
def solution(A):
dic = {}
for i in A:
if dic.has_key(i):
dic[i] = dic.get(i) + 1
else:
dic.update({i: 1})
l = dic.keys()
for i in l:
if dic[i]*2 > len(A):
return i
else:
return -1
[/code]

2 thoughts on “360ship面试题”

1. Jerry Wang

360ship? 外企物流公司么？

1. 李 志豪 Post author

恩，一个物流公司