solves merge intervals

Author: anishLearnsToCode

README.md

@@ -54,6 +54,7 @@
 |  53  | [Maximum SubArray](https://leetcode.com/problems/maximum-subarray)                                                                                        |                                 [![Java](assets/java.png)](src/MaximumSubArray.java) [![Python](assets/python.png)](python/maximum_sum_subarray.py)                                  |                                                                                                                                   |
 |  54  | [Spiral Matrix](https://leetcode.com/problems/spiral-matrix)                                                                                              |                                                                  [![Java](assets/java.png)](src/SpiralMatrix.java)                                                                   |                                                                                                                                   |
 |  55  | [Jump Game](https://leetcode.com/problems/jump-game)                                                                                                      |                                                                    [![Java](assets/java.png)](src/JumpGame.java)                                                                     |                                                                                                                                   |
+|  56  | [Merge Intervals](https://leetcode.com/problems/merge-intervals)                                                                                          |                                                                 [![Java](assets/java.png)](src/MergeIntervals.java)                                                                  |                                                                                                                                   |
 |  58  | [Length of Last Word](https://leetcode.com/problems/length-of-last-word)                                                                                  |                                 [![Java](assets/java.png)](src/LengthOfLastWord.java) [![Python](assets/python.png)](python/length_of_last_word.py)                                  |                                                                                                                                   |
 |  66  | [Plus One](https://leetcode.com/problems/plus-one)                                                                                                        |                                           [![Java](assets/java.png)](src/PlusOne.java) [![Python](assets/python.png)](python/plus_one.py)                                            |                                                                                                                                   |
 |  67  | [Add Binary](https://leetcode.com/problems/add-binary)                                                                                                    |                                         [![Java](assets/java.png)](src/AddBinary.java) [![Python](assets/python.png)](python/add_binary.py)                                          |                                                                                                                                   |

src/MergeIntervals.java

@@ -0,0 +1,35 @@
+// https://leetcode.com/problems/merge-intervals/submissions
+// T: O(n log(n))
+// S: O(n)
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.List;
+
+public class MergeIntervals {
+    public int[][] merge(int[][] intervals) {
+        Arrays.sort(intervals, Comparator.comparingInt(interval  -> interval[0]));
+        final List<int[]> mergedIntervals = new ArrayList<>();
+        int start = intervals[0][0], stop = intervals[0][1];
+        for (int i = 1 ; i < intervals.length ; i++) {
+            if (intervals[i][0] <= stop) stop = Math.max(stop, intervals[i][1]);
+            else {
+                mergedIntervals.add(new int[] {start, stop});
+                start = intervals[i][0];
+                stop = intervals[i][1];
+            }
+        }
+        mergedIntervals.add(new int[] {start, stop});
+        return toArray(mergedIntervals);
+    }
+
+    private int[][] toArray(List<int[]> list) {
+        int[][] result = new int[list.size()][2];
+        int i = 0;
+        for (int[] interval : list) {
+            result[i++] = interval;
+        }
+        return result;
+    }
+}