added Insert Interval (hard)

Author: minhyeong-joe

Hard/InsertInterval/README.md

@@ -0,0 +1,21 @@
+
+# Insert Interval
+[Leetcode Link](https://leetcode.com/problems/insert-interval/)
+
+## Problem:
+
+Given a set of *non-overlapping* intervals, insert a new interval into the intervals (merge if necessary).
+
+You may assume that the intervals were initially sorted according to their start times.
+
+## Example:
+
+```
+Input: intervals = [[1,3],[6,9]], newInterval = [2,5]
+Output: [[1,5],[6,9]]
+```
+```
+Input: intervals = [[1,2],[3,5],[6,7],[8,10],[12,16]], newInterval = [4,8]
+Output: [[1,2],[3,10],[12,16]]
+Explanation: Because the new interval [4,8] overlaps with [3,5],[6,7],[8,10].
+```

Hard/InsertInterval/solution.py

@@ -0,0 +1,32 @@
+from typing import List
+
+class Solution:
+ def insert(self, intervals: List[List[int]], newInterval: List[int]) -> List[List[int]]:
+ result = list()
+ # insert newInterval sorted by start time
+ insertIndex = 0
+ for i, interval in enumerate(intervals):
+ if newInterval[0] >= interval[0]:
+ insertIndex = i+1
+ intervals.insert(insertIndex, newInterval)
+ print(intervals)
+ # use queue to merge from low start time
+ while intervals:
+ cur = intervals.pop(0)
+ if not result:
+ result.append(cur)
+ continue
+ if result[-1][0] <= cur[0] <= result[-1][1]:
+ start = result[-1][0]
+ end = max(result[-1][1], cur[1])
+ result[-1] = [start, end]
+ else:
+ result.append(cur)
+ return result
+
+
+# test driver
+sol = Solution()
+intervals = [[2,3], [6,8]]
+newInterval = [4,7]
+print("Output:", sol.insert(intervals, newInterval))

README.md

@@ -77,6 +77,7 @@ Languages used: Java and Python
  - [Reducing Dishes](Hard/ReducingDishes)
  - [Longest Consecutive Sequence](Hard/LongestConsecutiveSequence)
  - [First Missing Positive](Hard/FirstMissingPositive)
+ - [Insert Interval](Hard/InsertInterval)
 
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