题目

方法

使用容器类保存，时间复杂度是不是O(n) 有待确定。

    public int longestConsecutive(int[] num) {
        if (num == null || num.length == 0) {
            return 0;
        }
        Set<Integer> set = new HashSet<Integer>();
        for (int i = 0; i < num.length; i++) {
            set.add(num[i]);
        }
        int max = 0;
        for (int i = 0; i < num.length; i++) {
            if (set.contains(num[i])) {
                int left = num[i] - 1;
                while(set.contains(left)) {
                    set.remove(left);
                    left--;
                }
                int right = num[i] + 1;    
                while(set.contains(right)) {
                    set.remove(right);
                    right++;
                }
                
                if (max < right - left - 1) {
                    max = right - left - 1;
                }
            }

        }
        return max;
    }

Longest Consecutive Sequence,布布扣,bubuko.com

Longest Consecutive Sequence

原文：http://blog.csdn.net/u010378705/article/details/35623651