Find Minimum in Rotated Sorted Array in Java

Find Minimum in Rotated Sorted Array in Java

This guide explains the intuition, optimized approach, and Java implementation for find minimum in rotated sorted array in java, with practical tips for interviews and production coding standards.

Problem

Array is sorted then rotated. Find the minimum value in O(log n).

Insight

Compare nums[mid] with nums[right]:

• If nums[mid] > nums[right], minimum is in right half
• Else, minimum is in left half including mid

Java Solution

class Solution {
    public int findMin(int[] nums) {
        int left = 0, right = nums.length - 1;

        while (left < right) {
            int mid = left + (right - left) / 2;

            if (nums[mid] > nums[right]) {
                left = mid + 1;
            } else {
                right = mid;
            }
        }

        return nums[left];
    }
}

Complexity

• Time: O(log n)
• Space: O(1)

Key Takeaways

• Start from the brute-force idea, then derive the optimized invariant.
• Use clean pointer/index boundaries to avoid off-by-one bugs.
• Validate against edge cases (empty input, single element, duplicates, extreme values).