标签：style blog http io color ar os for sp
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).
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.
Array Binary Search
class Solution { public: int findPos(int a[],int left,int right){ if(left>right) return -1; int mid=left+(right-left)/2; if(a[left]<=a[mid]){ int pos=findPos(a,mid+1,right); if(pos==-1) return left; else return a[left]<=a[pos] ? left : pos; }else{ int pos=findPos(a,left,mid-1); if(pos==-1) return mid; else return a[pos]<a[mid] ? pos : mid; } } int bsearch(int a[],int left,int right,int key){ if(left>right) return -1; int mid=left+(right-left)/2; if(a[mid]==key) return mid; else if(a[mid]<key) return bsearch(a,mid+1,right,key); else return bsearch(a,left,mid-1,key); } int search(int A[], int n, int target) { int pos=findPos(A,0,n-1); int index=bsearch(A,0,pos-1,target); if(index!=-1) return index; else return bsearch(A,pos,n-1,target); } };
Search in Rotated Sorted Array
标签：style blog http io color ar os for sp
原文地址：http://www.cnblogs.com/li303491/p/4078928.html
