问题陈述: 有一个按升序排序的整数数组 nums (具有不同的值)。 在传递给您的函数之前,nums 可能会在未知的枢轴索引 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.
我已经编写了与该问题提交中给出的完全相同的代码,但是,我的输出之一失败了。我找不到原因。我是否缺少一些逻辑?请建议。
class Solution {
public int search(int[] nums, int target) {
int left = nums[0];
int right = nums.length - 1;
while (left <= right) {
int mid = (left + right) / 2;
if (target == nums[mid]) {
return mid;
} else {
// if left sorted
if (nums[left] <= nums[mid]) {
if (nums[left] <= target && target < nums[mid]) {
right = mid - 1;
} else {
left = mid + 1;
}
} else {
// else right sorted
if (nums[mid] < target && target <= nums[right]) {
left = mid + 1;
} else {
right = mid - 1;
}
}
}
}
return -1;
}
}
代码无法提供以下输出: nums = [6,7,1,2,3,4,5] 且目标 = 7 ; 预期输出 = 1,实际输出 = -1
令人厌恶的错误,我们通常不会过多关注简单的初始化;)
改变
int left = nums[0];
到
int left = 0;