added remove covered intervals

Author: codenitros

october/removeCoveredIntervals.cpp

@@ -0,0 +1,47 @@
+/*
+
+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.
+
+
+Input: intervals = [[1,4],[3,6],[2,8]]
+Output: 2
+Explanation: Interval [3,6] is covered by [2,8], therefore it is removed.
+
+*/
+
+//solution
+
+using interval = vector<int>;
+
+bool comparator(interval a, interval b)
+{
+    if(a[0] == b[0]){
+        return a[1] > b[1];
+    }
+    return a[0] < b[0];
+}
+
+class Solution {
+public:
+    int removeCoveredIntervals(vector<vector<int>>& intervals) {
+        //sort based on starting interval
+        
+        sort(intervals.begin(),intervals.end(),comparator);
+        int ans=intervals.size();
+        int maxEnd = 0;
+        for(interval cur:intervals)
+        {
+            int curEnd = cur[1];
+            if(curEnd <= maxEnd){
+                ans--;
+            }
+            
+            maxEnd = max(maxEnd, curEnd);
+        }
+        return ans;
+    }
+};