相鄰兩數的最大差值

題目：相鄰兩數的最大差值

//主要功能函式
public static int maxGap(int[] nums) {
        if (nums == null || nums.length < 2) {
            return 0;
        }
        int len = nums.length;
        int min = Integer.MAX_VALUE;
        int max = Integer.MIN_VALUE;
        //求出一組數中的最小值和最大值
        for (int i = 0; i < len; i++) {
            min = Math.min(min, nums[i]);
            max = Math.max(max, nums[i]);
        }
        if (min == max) {
            return 0;
        }
        //hashNum陣列標記該號桶是否有值
        //求出該號桶的最大值，下標表示桶的位置
        //求出該號桶的最小值，下標表示桶的位置
        boolean[] hasNum = new boolean[len + 1];
        int[] maxs = new int[len + 1];
        int[] mins = new int[len + 1];
        int bid = 0;
        for (int i = 0; i < len; i++) {
            bid = bucket(nums[i], len, min, max);
            mins[bid] = hasNum[bid] ? Math.min(mins[bid], nums[i]) : nums[i];
            maxs[bid] = hasNum[bid] ? Math.max(maxs[bid], nums[i]) : nums[i];
            hasNum[bid] = true;
        }
        int res = 0;
        int lastMax = maxs[0];
        int i = 1;
        for (; i <= len; i++) {
            if (hasNum[i]) {
                res = Math.max(res, mins[i] - lastMax);
                lastMax = maxs[i];
            }
        }
        return res;
    }

//求出在幾號桶
public static int bucket(long num, long len, long min, long max) {
        return (int) ((num - min) * len / (max - min));
    }