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lc33.java
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lc33.java
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package code;
/*
* 31. Search in Rotated Sorted Array
* 题意:在翻转有序数组中查找指定数
* 难度:Medium
* 分类:Array, Binary Search
* 思路:二分查找的思路,多了一步判断,判断哪部分有序,是否在这部分中
* Tips:注意边界判断,是否有等号
*/
public class lc33 {
public static void main(String[] args) {
int[] nums = {1,3};
System.out.println(search(nums, 3));
}
public static int search(int[] nums, int target) {
int start = 0;
int end = nums.length-1;
while(start<=end){
if(start==end){
if(nums[start]==target)
return start;
return -1;
}
int mid = (start+end)/2;
if(target == nums[mid])
return mid;
if(nums[mid]>nums[end]){//左边是有序的
if(nums[start]<=target && target<=nums[mid])
end = mid-1;
else
start = mid+1;
}else{//右边是有序的
if(nums[mid]<=target && target<=nums[end])
start = mid+1;
else
end =mid-1;
}
}
return -1;
}
}