// 646. Maximum Length of Pair Chain #include "leetcode.h" /* * given a n array of 'n' pairs, where 'pairs[i]= [lefti, righti]' and 'left[i] * < right[i]'. a pair 'p2 = [c, d]' follows a pair 'p1 = [a, b]' if 'b < c'. a * chain of pairs can be formed in this fashion. return the length of the * longest chain which can be formed. you do not need to use up all the given * intervals. you can select pairs in any order. */ class Solution { static bool cmp(vector &a, vector &b) { return a[1] < b[1]; } public: int findLongestChain(vvd & pairs) { sort(pairs.begin(), pairs.end(), cmp); int cnt = 0; for (int i = 0, j = 0; j < pairs.size(); j++) if (!j || pairs[i][1] < pairs[j][0]) { cnt++; i = j; } return cnt; } }; int main() { Solution obj; vvd p1 = {{1, 2}, {2, 3}, {3, 4}}, p2 = {{1, 2}, {7, 8}, {4, 5}}; printf("%d\n", obj.findLongestChain(p1)); // expect: 2 printf("%d\n", obj.findLongestChain(p2)); // expect: 3 }