164. Maximum Gap

Leetcode Sort

Given an unsorted array, find the maximum difference between the successive elements in its sorted form.

Return 0 if the array contains less than 2 elements.

Example 1:

Input: [3,6,9,1]
Output: 3
Explanation: The sorted form of the array is [1,3,6,9], either
             (3,6) or (6,9) has the maximum difference 3.

Example 2:

Input: [10]
Output: 0
Explanation: The array contains less than 2 elements, therefore return 0.

Note:

• You may assume all elements in the array are non-negative integers and fit in the 32-bit signed integer range.
• Try to solve it in linear time/space.

分析

最大间距。最直接的方法就是一五一十的按照题目描述的做：先排序，然后看看相邻元素的最大间距。

public int maximumGap(int[] nums) {
    if (nums == null || nums.length < 2) return 0;
    Arrays.sort(nums);
    int maxGap = -1;
    for (int i = 1; i < nums.length; i++)
        maxGap = Math.max(maxGap, Math.abs(nums[i] - nums[i - 1]));
    return maxGap;
}

第二种巧妙的方法使用基数排序。

还有一种方法就是使用桶排序。