LeetCode646. Maximum Length of Pair Chain

646. Maximum Length of Pair Chain

题目：

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]

题目分析：非常简单的一道题，但是题目说的是动态规划，但是我并没有用动态规划去做。

代码：

bool cmp(vector<int> a, vector<int> b) {    if (a[0] < b[0]) return true;    else if (a[0] == b[0]) return a[1] <= b[1];    else return false;}class Solution {public:    int findLongestChain(vector<vector<int>>& pairs) {        if (pairs.empty()) return 0;        sort(pairs.begin(), pairs.end(), cmp);        int res = 1, tmp1 = pairs[0][0], tmp2 = pairs[0][1];        for (int i = 1; i < pairs.size(); i++) {            if (pairs[i][0] > tmp2) {                res++;                tmp2 = pairs[i][1];            }            tmp2 = min(pairs[i][1], tmp2);        }        return res;    }};