标签：style blog io ar color sp for on div
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.
Solution:
1 public class Solution { 2 public int longestConsecutive(int[] num) { 3 4 Set<Integer> set = new HashSet<Integer>(); 5 for (int i=0;i<num.length;i++) set.add(num[i]); 6 int maxLen = 0; 7 int index = 0; 8 while (index<num.length){ 9 if (!set.contains(num[index])){ 10 index++; 11 continue; 12 } 13 14 int len =0; 15 int val = num[index]; 16 while (set.contains(val)){ 17 set.remove(val); 18 len++; 19 val--; 20 } 21 val = num[index]+1; 22 while (set.contains(val)){ 23 set.remove(val); 24 len++; 25 val++; 26 } 27 if (maxLen<len) maxLen=len; 28 index++; 29 } 30 31 32 return maxLen; 33 34 } 35 36 }
Leetcode-Longest Consecutive Sequence
标签：style blog io ar color sp for on div
原文地址：http://www.cnblogs.com/lishiblog/p/4158928.html
