646. Maximum Length of Pair Chain

You are given n pairs of numbers. In every pair, the first number is always smaller than the second number.

Now, we define a pair (c, d) can follow another pair (a, b) if and only if b < c. Chain of pairs can be formed in this fashion.

Given a set of pairs, find the length longest chain which can be formed. You needn't use up all the given pairs. You can select pairs in any order.

Example 1:

Input: [[1,2], [2,3], [3,4]]Output: 2Explanation: The longest chain is [1,2] -> [3,4]

Note:

1. The number of given pairs will be in the range [1, 1000].

---

Seen this question in a real interview before?

public class Solution {    class Comp implements Comparator<int[]> {public int compare(int[] a1, int[] a2) {return a1[1] < a2[1] ? -1 : a1[1] > a2[1] ? 1 : a1[0] < a2[0] ? -1 : a1[0] == a2[0] ? 0 : 1;}}    public int findLongestChain(int[][] pairs) {        if (pairs.length == 0)return 0;Arrays.sort(pairs, new Comp());int re = 1;int cur = pairs[0][1];for (int i = 1; i < pairs.length; ++i) {if (pairs[i][0] == pairs[i - 1][0] || pairs[i][0] <= cur)continue;else {re += 1;cur = pairs[i][1];}}return re;    }}