Add find-minimum-in-rotated-sorted-array solution in TypeScript

Author: Jeehay28

find-minimum-in-rotated-sorted-array/Jeehay28.ts

@@ -0,0 +1,48 @@
+// Approach 2: binary search
+// Time Complexity: ✅ O(log n)
+// Space Complexity: O(1)
+
+function findMin(nums: number[]): number {
+
+    let left = 0
+    let right = nums.length - 1
+
+    while(left < right) {
+
+        const mid = Math.floor((left + right) / 2)
+
+        if(nums[mid] > nums[right]) {
+            // the min must be to the right of mid
+            left = mid + 1
+        } else {
+            // the mins could be mid or to the left
+            right = mid
+        }
+    }
+
+    return nums[left]  
+};
+
+
+// Approach 1:
+// Time Complexity: ❌ O(n)
+// Space Complexity: O(1)
+
+// function findMin(nums: number[]): number {
+//   // input: an array of length n sorted in ascending order
+//   // rotate: a[n-1], a[0], ..., a[n-2]
+//   // time complexity allowed: O(log n)
+
+//   let first = nums[0];
+//   let last = nums[nums.length - 1];
+//   let cnt = 0;
+
+//   while (first > last) {
+//     first = last;
+//     cnt += 1;
+//     last = nums[nums.length - 1 - cnt];
+//   }
+
+//   return first;
+// }
+