leetcode117:search-rotated-sorted-array
阿新 • • 發佈：2020-08-01
題目描述
給出一個轉動過的有序陣列，你事先不知道該陣列轉動了多少(例如,0 1 2 4 5 6 7可能變為4 5 6 7 0 1 2).
在陣列中搜索給出的目標值，如果能在陣列中找到，返回它的索引，否則返回-1。
假設陣列中不存在重複項。
Suppose a sorted array is rotated at some pivot unknown to you beforehand.
(i.e.,0 1 2 4 5 6 7might become4 5 6 7 0 1 2).
You are given a target value to search. If found in the array return its index, otherwise return -1.
You may assume no duplicate exists in the array.
示例1
輸入
複製[1],0
輸出
複製-1
class Solution {
public:
int search(int A[], int n, int target) {
if(A == nullptr||n==0)
return -1;
int left = 0;
int right = n-1;
while(left<=right){
int mid = left + (right - left)/2;
if(A[mid] == target)return mid;
if(A[left] <= A[mid]){
if(A[left]<=target&&A[mid]>target)
right = mid-1;
else
left = mid+1;
}
else{
if(A[mid]<target&&A[right]>=target)
left = mid+1;
else
right = mid-1;
}
}
return -1;
}
};