package leetCode_128;

import java.util.HashMap;

/**

* @author dimdark

* @date 2017-09-16

* @time 10:35 PM

*/

public class Solution {

public int longestConsecutive(int[] nums) {

if (nums == null) return 0;

int maxLen = 0, len, left, right;

HashMap<Integer, Integer> map = new HashMap<Integer, Integer>();

for (int num : nums) {

if (!map.containsKey(num)) { // not contain

// left = map.containsKey(num - 1) ? map.get(num - 1) : 0;

left = map.getOrDefault(num - 1, 0);

// right = map.containsKey(num + 1) ? map.get(num + 1) : 0;

right = map.getOrDefault(num + 1, 0);

len = left + right + 1;

maxLen = (maxLen < len) ? len : maxLen; // update maximum

map.put(num, len);

// core thought: put the current max length to left boundary and right boundary

map.put(num - left, len);

map.put(num + right, len);

}

}

return maxLen;

}

}