Create mergeInterval.java

Author: Anova07

LeetCode/mergeInterval.java

@@ -0,0 +1,45 @@
+/*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.
+
+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] overlaps, merge them into [1,6].
+
+
+
+Sorting takes O(n log(n)) and merging the intervals takes O(n). So, the resulting algorithm i.e. sorting, takes O(n log(n)).
+*/
+
+ 
+class Solution {
+  
+	public int[][] merge(int[][] intervals) {
+		if (intervals.length <= 1)
+			return intervals;
+
+		// Sort on th basis of ascending starting point
+		Arrays.sort(intervals, (i1, i2) -> Integer.compare(i1[0], i2[0]));
+
+		List<int[]> result = new ArrayList<>();
+		int[] newInterval = intervals[0];
+		result.add(newInterval);
+    
+    
+		for (int[] interval : intervals) {
+			if (interval[0] <= newInterval[1])
+        // Overlapping intervals, move the end if needed
+         // overlap condition (update the end pointer)
+
+				newInterval[1] = Math.max(newInterval[1], interval[1]);
+      
+			else {                             
+        // Disjoint intervals, add the new interval to the list
+        
+				newInterval = interval;
+				result.add(newInterval);
+			}
+		}
+
+		return result.toArray(new int[result.size()][]);
+	}
+}