0056-merge-intervals.rb

# frozen_string_literal: true

# 56. Merge Intervals
# https://leetcode.com/problems/merge-intervals
# Medium

=begin
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.

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] overlap, 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:
* 1 <= intervals.length <= 104
* intervals[i].length == 2
* 0 <= starti <= endi <= 104
=end

# @param {Integer[][]} intervals
# @return {Integer[][]}
defmerge(intervals)
result=[]

intervals.sort_by{ |interval| interval[0]}.eachdo |interval|
if !result.empty? && interval[0] <= result[-1][1]
result[-1][1]=[result[-1][1],interval[1]].max
else
result << interval
end
end

result
end

# **************** #
# TEST #
# **************** #

require"test/unit"
classTest_merge < Test::Unit::TestCase
deftest_
assert_equal([[1,6],[8,10],[15,18]],merge([[1,3],[2,6],[8,10],[15,18]]))
assert_equal([[1,5]],merge([[1,4],[4,5]]))
end
end