首页 > 代码库 > Leetcode-Longest Consecutive Sequence
Leetcode-Longest Consecutive Sequence
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.
Analysis:
We use hash table to store each element. For element, we search the value smaller and larger than it in the table and find out the current max len. We mark every visited element.
Solution:
1 public class Solution { 2 public int longestConsecutive(int[] num) { 3 if (num.length==0 || num.length==1) return num.length; 4 5 Map<Integer,Boolean> map = new HashMap<Integer,Boolean>(); 6 for (int i=0;i<num.length;i++) 7 map.put(num[i],false); 8 9 int maxLen = 0;10 for (int i=0;i<num.length;i++){11 int curVal = num[i];12 if (map.get(curVal)) continue;13 14 int curLen = 1;15 map.put(curVal,true);16 int val = curVal-1;17 while (map.containsKey(val) && !map.get(val)){18 curLen++;19 map.put(val,true);20 val--;21 }22 val = curVal+1;23 while (map.containsKey(val) && !map.get(val)){24 curLen++;25 map.put(val,true);26 val++;27 }28 if (maxLen<curLen) maxLen = curLen;29 }30 31 return maxLen;32 }33 }
Leetcode-Longest Consecutive Sequence
声明：以上内容来自用户投稿及互联网公开渠道收集整理发布，本网站不拥有所有权，未作人工编辑处理，也不承担相关法律责任，若内容有误或涉及侵权可进行投诉： 投诉/举报 工作人员会在5个工作日内联系你，一经查实，本站将立刻删除涉嫌侵权内容。