add Merge Intervals solution

Author: HoonDongKang

merge-intervals/HoonDongKang.ts

@@ -0,0 +1,58 @@
+/**
+ * [Problem]: [56] Merge Intervals
+ * (https://leetcode.com/problems/merge-intervals/description/)
+ */
+function merge(intervals: number[][]): number[][] {
+    //시간복잡도 O(n^2)
+    //공간복잡도 O(n)
+    function bruteForceFunc(intervals: number[][]): number[][] {
+        const result: number[][] = [];
+        const visited = new Set<number>();
+
+        for (let i = 0; i < intervals.length; i++) {
+            if (visited.has(i)) continue;
+            visited.add(i);
+
+            while (true) {
+                let hasMerged = false;
+                for (let j = 0; j < intervals.length; j++) {
+                    if (visited.has(j)) continue;
+
+                    const [curA, curB] = intervals[i];
+                    const [nextA, nextB] = intervals[j];
+
+                    if (curA <= nextB && nextA <= curB) {
+                        visited.add(j);
+                        intervals[i] = [Math.min(curA, nextA), Math.max(curB, nextB)];
+
+                        hasMerged = true;
+                    }
+                }
+                if (!hasMerged) break;
+            }
+            result.push(intervals[i]);
+        }
+        return result;
+    }
+
+    //시간복잡도 O(nlog n)
+    //공간복잡도 O(n)
+    function sortFunc(intervals: number[][]): number[][] {
+        if (!intervals.length) return intervals;
+        intervals.sort((a, b) => a[0] - b[0]);
+
+        const result: number[][] = [intervals[0]];
+        for (let i = 0; i < intervals.length; i++) {
+            const prev = result[result.length - 1];
+            const cur = intervals[i];
+
+            if (cur[0] <= prev[1]) {
+                prev[1] = Math.max(prev[1], cur[1]);
+            } else {
+                result.push(cur);
+            }
+        }
+
+        return result;
+    }
+}