feat: inset-interval

Author: gwbaik9717

insert-interval/gwbaik9717.js

@@ -0,0 +1,57 @@
+// Time complexity: O(n)
+// Space complexity: O(n)
+
+/**
+ * @param {number[][]} intervals
+ * @param {number[]} newInterval
+ * @return {number[][]}
+ */
+var insert = function (intervals, newInterval) {
+  // 1. Insert newInterval
+  const candidates = [];
+  let inserted = false;
+
+  if (intervals.length === 0) {
+    candidates.push(newInterval);
+  }
+
+  for (const [start, end] of intervals) {
+    const [newStart, newEnd] = newInterval;
+
+    if (!inserted) {
+      if (newStart <= start) {
+        candidates.push([newStart, newEnd]);
+        inserted = true;
+      }
+    }
+
+    candidates.push([start, end]);
+  }
+
+  if (!inserted) {
+    candidates.push(newInterval);
+  }
+
+  // 2. Merge if needed
+
+  const answer = [];
+
+  for (const [start, end] of candidates) {
+    if (answer.length === 0) {
+      answer.push([start, end]);
+      continue;
+    }
+
+    const [compareStart, compareEnd] = answer.at(-1);
+
+    if (compareEnd >= start) {
+      answer.pop();
+      answer.push([Math.min(start, compareStart), Math.max(end, compareEnd)]);
+      continue;
+    }
+
+    answer.push([start, end]);
+  }
+
+  return answer;
+};