Merge Intervals

Tags : array, sorting, leetcode, cpp, medium

Given an array of intervals where intervals[i] = [starti, endi], merge all overlapping intervals, and return an array of the non-overlapping intervals that cover all the intervals in the input.

Examples #

Example 1:

Input: intervals = [[1,3],[2,6],[8,10],[15,18]]
Output: [[1,6],[8,10],[15,18]]
Explanation: Since intervals [1,3] and [2,6] overlaps, merge them into [1,6].

Example 2:

Input: intervals = [[1,4],[4,5]]
Output: [[1,5]]
Explanation: Intervals [1,4] and [4,5] are considered overlapping.

Constraints #

Solutions #

class Solution {
public:
    vector<vector<int>> merge(vector<vector<int>>& intervals) {
      sort(intervals.begin(), intervals.end());
      vector<vector<int>> res;
      for(auto i: intervals){
        if(res.empty() or res.back()[1] < i[0])
          res.push_back(i);
        else
          res.back()[1] = max(res.back()[1], i[1]);
      }
      return res;
    }
};