non-overlapping intervals

Author: fishercoder1534

MEDIUM/src/medium/NonOverlappingIntervals.java

@@ -0,0 +1,43 @@
+package medium;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+
+import classes.Interval;
+
+public class NonOverlappingIntervals {
+/**Looked at these two posts: https://discuss.leetcode.com/topic/65828/java-solution-with-clear-explain
+ * and https://discuss.leetcode.com/topic/65594/java-least-is-most
+ * Sort the intervals by their end time, if equal, then sort by their start time.*/
+    public static int eraseOverlapIntervals(Interval[] intervals) {
+        Collections.sort(Arrays.asList(intervals), new Comparator<Interval>(){
+            @Override
+            public int compare(Interval o1, Interval o2) {
+                if(o1.end != o2.end) return o1.end - o2.end;
+                else return o2.start - o1.start;
+            }
+        });
+        int end = Integer.MIN_VALUE;
+        int count = 0;
+        for(Interval interval : intervals){
+            if(interval.start >= end) end = interval.end;
+            else count++;
+        }
+        return count;
+    }
+    
+    public static void main(String...args){
+        //[[1,100],[11,22],[1,11],[2,12]]
+        Interval interval1 = new Interval(1,100);
+        Interval interval2 = new Interval(11,22);
+        Interval interval3 = new Interval(1,11);
+        Interval interval4 = new Interval(2,12);
+        Interval[] intervals = new Interval[]{interval1, interval2, interval3, interval4};
+        
+        
+        System.out.println(eraseOverlapIntervals(intervals));
+    }
+
+}

README.md

@@ -1,9 +1,10 @@
 # fishercoderLeetcode
 |  #  |      Title     |   Solutions   | Time          | Space         | Difficulty  | Tag          | Notes
 |-----|----------------|---------------|---------------|---------------|-------------|--------------|-----
-|453|[Minimum Moves to Equal Array Elementss](https://leetcode.com/problems/minimum-moves-to-equal-array-elements/)|[Solution](../../blob/master/EASY/src/easy/MinimumMovestoEqualArrayElements.java)| O(n)|O(1) | Easy|
+|453|[Minimum Moves to Equal Array Elements](https://leetcode.com/problems/minimum-moves-to-equal-array-elements/)|[Solution](../../blob/master/EASY/src/easy/MinimumMovestoEqualArrayElements.java)| O(n)|O(1) | Easy|
 |447|[Number of Boomerangs](https://leetcode.com/problems/number-of-boomerangs/)|[Solution](../../blob/master/EASY/src/easy/NumberofBoomerangs.java)| O(n^2)|O(n) | Easy| HashMap
 |441|[Arranging Coins](https://leetcode.com/problems/arrange-coins/)|[Solution](../../blob/master/EASY/src/easy/ArrangingCoins.java)| O(n)|O(1) | Easy|
+|435|[Non-overlapping Intervals](https://leetcode.com/problems/non-overlapping-intervals/)|[Solution](../../blob/master/MEDIUM/src/medium/NonOverlappingIntervals.java) | O(nlogn) |O(1) | Medium| Greedy
 |419|[Battleships in a Board](https://leetcode.com/problems/battleships-in-a-board/)|[Solution](../../blob/master/MEDIUM/src/medium/BattleshipsinaBoard.java) | O(n^2) |O(1) | Medium| DFS
 |417|[Pacific Atlantic Water Flow](https://leetcode.com/problems/pacific-atlantic-water-flow/)|[Solution](../../blob/master/MEDIUM/src/medium/PacificAtlanticWaterFlow.java) | O(m*n*Max(m,n)) |O(m*n) | Medium| DFS
 |415|[Add Strings](https://leetcode.com/problems/add-strings/)|[Solution](../../blob/master/EASY/src/easy/AddStrings.java)| O(n)|O(1) | Easy|