标签：style blog color for io leetcode
Given an unsorted array of integers, find the length of the longest consecutive elements sequence.
For example,
Given [100, 4, 200, 1, 3, 2],
The longest consecutive elements sequence is [1, 2, 3, 4]. Return its length: 4.
Your algorithm should run in O(n) complexity.
这个方法依赖hashSet，空间复杂度O(N)
Solution：
public class Solution { public int longestConsecutive(int[] num) { HashSet<Integer> set = new HashSet<Integer>(); int length = 0; for(int e : num){ set.add(e); } for(int i = 0; i < num.length;i++){ int l = num[i] -1; int r = num[i] +1; int c = 1; while(set.contains(l)){ c++; set.remove(l); l--; } while(set.contains(r)){ c++; set.remove(r); r++; } length = Math.max(length,c); } return length; } }
LeetCode：Longest Consecutive Sequence,布布扣,bubuko.com
LeetCode：Longest Consecutive Sequence
标签：style blog color for io leetcode
原文地址：http://www.cnblogs.com/yeek/p/3821218.html
