Add non-overlapping-intervals solution

Author: Jeehay28

non-overlapping-intervals/Jeehay28.js

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+// 🚀 Greedy Algorithm
+// ✅ Time Complexity: O(n log n), where n is the number of intervals
+// - Sorting the intervals: O(n log n)
+// - Iterating through intervals: O(n)
+
+// ✅ Space Complexity: O(1), No other data structures are used,
+
+/**
+ * @param {number[][]} intervals
+ * @return {number}
+ */
+var eraseOverlapIntervals = function (intervals) {
+  // ✅ Sorting by end time ensures that we keep intervals that finish the earliest, reducing the chances of overlap with the subsequent intervals.
+  // ❌ Sorting by start time would lead to a greedy choice too early, causing unnecessary removals.
+  intervals.sort((a, b) => a[1] - b[1]);
+
+  let removalCnt = 0;
+
+  let prevEnd = intervals[0][1];
+
+  for (let i = 1; i < intervals.length; i++) {
+    const [start, end] = intervals[i];
+
+    if (start < prevEnd) {
+      removalCnt += 1; // Increment removal count for an overlap
+    } else {
+      prevEnd = end;
+    }
+  }
+  return removalCnt;
+};
+