#278 Merge Intervals

Author: forest000014

merge-intervals/forest000014.java

@@ -0,0 +1,29 @@
+/*
+# Time Complexity: O(nlogn)
+# Space Complexity: O(n)
+*/
+
+class Solution {
+    public int[][] merge(int[][] intervals) {
+        int n = intervals.length;
+
+        Arrays.sort(intervals, (a, b) -> a[0] - b[0]);
+
+        ArrayList<int[]> ans = new ArrayList<>();
+        ans.add(new int[2]);
+        ans.get(0)[0] = intervals[0][0];
+        ans.get(0)[1] = intervals[0][1];
+
+        for (int i = 1; i < n; i++) {
+            if (ans.get(ans.size() - 1)[1] < intervals[i][0]) {
+                ans.add(new int[2]);
+                ans.get(ans.size() - 1)[0] = intervals[i][0];
+                ans.get(ans.size() - 1)[1] = intervals[i][1];
+            } else {
+                ans.get(ans.size() - 1)[1] = Math.max(ans.get(ans.size() - 1)[1], intervals[i][1]);
+            }
+        }
+
+        return ans.toArray(new int[ans.size()][]);
+    }
+}