153. Find Minimum in Rotated Sorted Array (#85)

Author: Kohei Asai

solutions/findMinimumInRotatedSortedArray.test.ts

@@ -0,0 +1,18 @@
+import findMin from "./findMinimumInRotatedSortedArray";
+
+const TEST_CASES = new Map([
+  [[3, 4, 5, 1, 2], 1],
+  [[4, 5, 6, 7, 0, 1, 2], 0],
+  [[3, 1, 2], 1],
+  [[1, 2, 3, 4, 5, 6], 1],
+  [[2, 1], 1],
+  [[1], 1]
+]);
+
+describe("153. Find Minimum in Rotated Sorted Array", () => {
+  for (const [args, expected] of TEST_CASES.entries()) {
+    test(`when [${args.join(", ")}]`, () => {
+      expect(findMin(args)).toBe(expected);
+    });
+  }
+});

solutions/findMinimumInRotatedSortedArray.ts

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+// 153. Find Minimum in Rotated Sorted Array
+// https://leetcode.com/problems/find-minimum-in-rotated-sorted-array/
+export default function findMin(nums: number[]) {
+  let from = 0;
+  let to = nums.length;
+
+  while (to - from >= 2) {
+    const middle = Math.floor((from + to) / 2);
+
+    if (nums[middle - 1] >= nums[to - 1]) {
+      from = middle;
+    } else {
+      to = middle;
+    }
+  }
+
+  return nums[from];
+}