Divide Intervals Into Minimum Number of Groups

arraytwo pointersgreedy

Problem Statement

You are given a 2D integer array intervals where intervals[i] = [left _i , right _i ] represents the inclusive interval [left _i , right _i ] .

You have to divide the intervals into one or more groups such that each interval is in exactly one group, and no two intervals that are in the same group intersect each other.

Return the minimum number of groups you need to make .

Two intervals intersect if there is at least one common number between them. For example, the intervals [1, 5] and [5, 8] intersect.

Examples

Example 1

Input: intervals = [[5,10],[6,8],[1,5],[2,3],[1,10]]
Output: 3
We can divide the intervals into the following groups:
- Group 1: [1, 5], [6, 8].
- Group 2: [2, 3], [5, 10].
- Group 3: [1, 10].
It can be proven that it is not possible to divide the intervals into fewer than 3 groups.

Example 2

Input: intervals = [[1,3],[5,6],[8,10],[11,13]]
Output: 1
None of the intervals overlap, so we can put all of them in one group.

Constraints

1 <= intervals.length <= 10 ^5

intervals[i].length == 2

1 <= left _i <= right _i <= 10 ^6

🤔

Medium

Difficulty

Topic Info

ModuleDSA

CategoryArray

Sub-topicTwo Pointers