# 374. Guess Number Higher or Lower

![](https://4272748102-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LekNH5IywF8mjBxFcnu%2F-Mflugy4H_mseeC83Jas%2F-Mfp7SNLJCpKS0uXvHdP%2Fimage.png?alt=media\&token=588b00be-97f4-4af7-8939-8bf3327c72ec)

![](https://4272748102-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LekNH5IywF8mjBxFcnu%2F-Mflugy4H_mseeC83Jas%2F-Mfp7VGjjs-vQwvHhlj1%2Fimage.png?alt=media\&token=e3dec9d0-a496-494e-9229-12d6d5646fee)

time: O(logn)

space:O(1)

```java
class Solution {
    public int search(int[] nums, int target) {
        int left = 0;
        int right = nums.length - 1;
        
        while (left <= right) {
            int mid = (left + right) >> 1;
            if (nums[mid] == target) {
                return mid;
            }
            // start mid right
            if (nums[left] <= nums[mid]) {
                if ( target <= nums[mid] && target >= nums[left]) {
                    right = mid - 1;
                } else {
                    left = mid + 1;
                }
            } else {
                if ( target >= nums[mid] && target <= nums[right]) {
                    left = mid + 1;
                } else {
                    right = mid - 1;
                }
            }
            
        }
        return -1;
    }
}
```