Solution added.

Author: 149ps

30 Days of October Challange/Week 1/4. Remove Covered Intervals/solution.py

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+"""
+Given a list of intervals, remove all intervals that are covered by another interval in the list.
+
+Interval [a,b) is covered by interval [c,d) if and only if c <= a and b <= d.
+
+After doing so, return the number of remaining intervals.
+
+
+
+Example 1:
+
+Input: intervals = [[1,4],[3,6],[2,8]]
+Output: 2
+Explanation: Interval [3,6] is covered by [2,8], therefore it is removed.
+Example 2:
+
+Input: intervals = [[1,4],[2,3]]
+Output: 1
+Example 3:
+
+Input: intervals = [[0,10],[5,12]]
+Output: 2
+Example 4:
+
+Input: intervals = [[3,10],[4,10],[5,11]]
+Output: 2
+Example 5:
+
+Input: intervals = [[1,2],[1,4],[3,4]]
+Output: 1
+
+
+Constraints:
+
+1 <= intervals.length <= 1000
+intervals[i].length == 2
+0 <= intervals[i][0] < intervals[i][1] <= 10^5
+All the intervals are unique.
+"""
+
+
+class Solution:
+    def removeCoveredIntervals(self, intervals: List[List[int]]) -> int:
+        intervals.sort(key=lambda a: a[0])
+        result = [intervals[0]]
+        for interval in intervals[1:]:
+            if interval[0] >= result[-1][0] and interval[1] <= result[-1][1]:
+                continue
+            elif interval[0] == result[-1][0] and interval[1] > result[-1][1]:
+                result.pop()
+                result.append(interval)
+            else:
+                result.append(interval)
+        return len(result)