leetcode-229.求众数(二)

class Solution {
    // 众数求解算法
    public List<Integer> majorityElement(int[] nums) {
        // 返回结果集
        List<Integer> result = new ArrayList<>();
        // 黑板(用于记录数据用)
        LinkedHashMap<Integer, Integer> blackboard = new LinkedHashMap<>();
        // 左边记录到的位置
        int leftPs = 0;
        // 右边记录到的位置
        int rightPs = nums.length - 1;

        while (leftPs <= rightPs) {
            for (int i = leftPs; i <= rightPs; i++) {
                if (blackboard.get(nums[i]) == null) {
                    blackboard.put(nums[i], 1);
                    if (leftPs > rightPs || 1>nums.length/3) {
                        result.add(nums[i]);
                    }
                    leftPs = i + 1;
                    break;
                } else {
                    int count = blackboard.get(nums[i]);
                    count++;
                    if (!result.contains(nums[i]) && count>nums.length/3) {
                        result.add(nums[i]);
                    }
                    blackboard.put(nums[i], count);
                    leftPs = i + 1;
                }
            }
            for (int i = rightPs; i >= leftPs; i--) {
                if (blackboard.get(nums[i]) == null) {
                    blackboard.put(nums[i], 1);
                    if (rightPs < leftPs || 1>nums.length/3) {
                        result.add(nums[i]);
                    }
                    rightPs = i - 1;
                    break;
                } else {
                    int count = blackboard.get(nums[i]);
                    count++;
                    if (!result.contains(nums[i]) && count>nums.length/3) {
                        result.add(nums[i]);
                    }
                    blackboard.put(nums[i], count);
                    rightPs = i - 1;
                }
            }
        }
        return result;
    }
}