Add week 12 solutions: merge-intervals

Author: gitsunmin

merge-intervals/gitsunmin.ts

@@ -0,0 +1,18 @@
+/**
+ * https://leetcode.com/problems/merge-intervals/
+ * time complexity : O(n)
+ * space complexity : O(n)
+ */
+
+function merge(intervals: number[][]): number[][] {
+    if (intervals.length === 0) return [];
+
+    intervals.sort((a, b) => a[0] - b[0]);
+
+    const merged: number[][] = [];
+    for (const interval of intervals) {
+        if (merged.length === 0 || merged[merged.length - 1][1] < interval[0]) merged.push(interval);
+        else merged[merged.length - 1][1] = Math.max(merged[merged.length - 1][1], interval[1]);
+    }
+    return merged;
+};