Non-overlapping Intervals - Codeprg

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Sunday, 16 August 2020

Non-overlapping Intervals

Non-overlapping Intervals


Non-overlapping Intervals

Given a collection of intervals, find the minimum number of intervals you need to remove to make the rest of the intervals non-overlapping.

     Input: [[1,2],[2,3],[3,4],[1,3]]

    Output: 1
    Explanation: [1,3] can be removed and the rest of intervals are non-overlapping.
    Input: [[1,2],[1,2],[1,2]]
    Output: 2
    Input: [[1,2],[2,3]] 

    Output: 0 

    class Solution {

    public:

        int eraseOverlapIntervals(vector<vector<int>>& intervals) {

            int n=intervals.size();

            if(n==1||n==0)return 0;

            sort(intervals.begin(),intervals.end(),[](const vector<int> &a , const vector<int> &b)->bool{

                return a[0]<b[0];

            });

            int i=1,ans=0,j=0;

            while(i<n)

            {

                if(intervals[i][0]<intervals[j][1])

                {

                    if(intervals[i][1]<intervals[j][1])

                        j=i;

                     ++ans;

                

                }else{

                  j=i;}

                ++i;

            }

            return ans;

        }

    };