Add non-overlapping-intervals solution in TS

Author: Jeehay28

non-overlapping-intervals/Jeehay28.ts

@@ -0,0 +1,46 @@
+// TC: O(n log n)
+// SC: O(1)
+function eraseOverlapIntervals(intervals: number[][]): number {
+  intervals.sort((a, b) => a[1] - b[1]);
+  // [1, 2], [2, 3], [1, 3], [3, 4]
+
+  let prevEnd = intervals[0][1];
+  let removalCount = 0;
+
+  for (let i = 1; i < intervals.length; i++) {
+    if (prevEnd > intervals[i][0]) {
+      removalCount++;
+      // skip current interval
+    } else {
+      prevEnd = intervals[i][1];
+    }
+  }
+
+  return removalCount;
+}
+
+
+// TC: O(n log n)
+// SC: O(1)
+// function eraseOverlapIntervals(intervals: number[][]): number {
+//   intervals.sort((a, b) => a[0] - b[0]);
+
+//   let prev = intervals[0];
+//   let cnt = 1;
+//   let removalCount = 0;
+
+//   while (cnt < intervals.length) {
+//     const current = intervals[cnt];
+
+//     if (prev[1] <= current[0]) {
+//       prev = current;
+//     } else {
+//       prev = [Math.min(prev[0], current[0]), Math.min(prev[1], current[1])];
+//       removalCount++;
+//     }
+//     cnt++;
+//   }
+
+//   return removalCount;
+// }
+