public int findMin(int[] nums) { return findMin(nums, 0, nums.length - 1); } public int findMin(int[] nums, int left, int right) { int mid = (left + right)/2; if(left == right) { return nums[left]; } if(nums[left] < nums[right]) { return nums[left];…

题目描述: python实现 Search in Rotated Sorted Array2 搜索旋转排序数组   中文: 假设按照升序排序的数组在预先未知的某个点上进行了旋转. ( 例如,数组 [0,0,1,2,2,5,6] 可能变为 [2,5,6,0,0,1,2] ). 编写一个函数来判断给定的目标值是否存在于数组中.若存在返回 true,否则返回 false. 英文: Suppose an array sorted in ascending order is rotated at some…

题目: Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand. (i.e.,  [0,1,2,4,5,6,7] might become  [4,5,6,7,0,1,2]). Find the minimum element. The array may contain duplicates. Example 1: Input: [1,3,5] Output: 1…

Follow up for "Search in Rotated Sorted Array":What if duplicates are allowed? Would this affect the run-time complexity? How and why? Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand. (i.e., 0 1 2 4…

This is a follow up problem to Search in Rotated Sorted Array, where nums may contain duplicates. 思路 该题是[leetcode]33. Search in Rotated Sorted Array旋转过有序数组里找目标值 的followup 唯一区别是加了line24-26的else语句来skip duplicates 代码 class Solution { public boolean sear…

问题描述:反转序列,但是有重复的元素,例如序列13111. 算法思路:如果元素有重复,那么left-mid,就不一定是有序的了,所以不能利用二分搜索,二分搜索必须是局部有序.针对有序序列的反转,如果有重复数据的话,那么必然是nums[left]=nums[mid]=nums[right],增加对这种情况的讨论即可. public boolean search(int[] nums, int target) { return binarySearch(nums, 0, nums.length -…

问题描述:寻找反转序列中最小的元素. 算法分析:和寻找某个数是一个道理,还是利用二分查找,总体上分两种情况.nums[left]<=nums[mid],else.但是,在截取子序列的时候,有可能得到一个顺序序列.如34512,截取后得到12,此时要对这种情况判断,因为是顺序的,所以,最左边的元素就是最小元素.这点区别于寻找target,因为寻找target是根据target和left,mid,right做比较判断的.所以就不用对这种顺序情况单独讨论了. public int findMin(in…

Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand. (i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2). Find the minimum element. You may assume no duplicate exists in the array. 题目标签:Array, Binary Search 题目给了…

 本文为大便一箩筐的原创内容,转载请注明出处,谢谢:http://www.cnblogs.com/dbylk/p/4032570.html 原题: Suppose a sorted array is rotated at some pivot unknown to you beforehand. (i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2). Find the minimum element. You may assume no duplica…

题意:有一个有序序列A,其内部可能有部分被旋转了,比如A[1...n]被转成A[mid...n]+A[1...mid-1],如果被旋转,只有这种形式.问最小元素是?(假设没有重复元素) 思路:如果是序没乱,直接返回A[1],如果乱了,二分查找还是可以的,O(1)可能就不行了. 二分要点:mid有可能就是所要找的最小元素,所以不能轻易写出l=mid+1这样的语句,可能最小值就被忽略过了,因为我们无法直接判断A[mid]是否就是最小值.所以尽量应该是l=mid这样写,但是要防止死循环. 具体来说,可…