Maximum Gap
要点：
问题：
- 为什么用n（元素个数）作为bucket的个数？
- 为什么用range公式
Given an unsorted array, find the maximum difference between the successive elements in its sorted form.
Try to solve it in linear time/space.
Return 0 if the array contains less than 2 elements.
You may assume all elements in the array are non-negative integers and fit in the 32-bit signed integer range.
class Solution(object):
def maximumGap(self, nums):
"""
:type nums: List[int]
:rtype: int
"""
maxv = -sys.maxint-1
minv = sys.maxint
n = len(nums)
if n==0: return 0
buckets = [[None, None] for i in range(n)]
for i in range(n):
maxv = max(maxv, nums[i])
minv = min(minv, nums[i])
r = (maxv-minv)/n+1
for i in range(n):
bn = (nums[i]-minv)/r
if not buckets[bn][0] or buckets[bn][0]>nums[i]:
buckets[bn][0]=nums[i]
if not buckets[bn][1] or buckets[bn][1]<nums[i]:
buckets[bn][1]=nums[i]
gap = 0
pre = buckets[0][1]
for i in range(1, n):
if buckets[i][0]:
gap = max(gap, buckets[i][0]-pre)
pre = buckets[i][1]
return gap