Search in rotated sorted array
There is an integer array nums sorted in ascending order (with distinct values).
Prior to being passed to your function, nums is possibly rotated at an unknown pivot index k (1 <= k < nums.length) such that the resulting array is [nums[k], nums[k+1], ..., nums[n-1], nums[0], nums[1], ..., nums[k-1]] (0-indexed). For example, [0,1,2,4,5,6,7] might be rotated at pivot index 3 and become [4,5,6,7,0,1,2].
Given the array nums after the possible rotation and an integer target, return the index of target if it is in nums, or -1 if it is not in nums.
You must write an algorithm with O(log n) runtime complexity.
var search = function(nums, target) {
let start = 0, end = nums.length - 1;
let mid = Math.floor((start + end) / 2);
while (start <= end) {
mid = Math.floor((start + end) / 2);
if (target === nums[mid]) {
return mid;
}
if (nums[start] <= nums[mid]) {
if (nums[start] <= target && nums[mid] >= target) {
end = mid - 1;
} else {
start = mid + 1;
}
} else {
if (nums[end] >= target && nums[mid] <= target) {
start = mid + 1;
} else {
end = mid - 1;
}
}
}
return -1;
}
There are many ways to solve this problem but they all use some variation of binary search or binary search applied many times. I think this may be a popular problem for interviews because it throws a wrench in the cookie cutter binary search template that many people memorize.
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