package Suanfa;
public class 二分查找和斐波那契数列 {
public static void main(String[] args) {
// TODO Auto-generated method stub
int []arr={1,2,3,6,7,8};
int index=二分查找递归(arr,9,0,arr.length);
System.out.println(index);
}
//二分查找非递归实现
public static int 二分查找非递归(int []arr,int key) {
int start=0,end=arr.length-1;
while(start<=end){
int mid=(start+end)/2;
//注意mid+1和mid-1,否则找不到会发生无限循环
if(key>arr[mid]){
start=mid+1;
}else if(key<arr[mid]){
end=mid-1;
}else if(key==arr[mid]){
return mid;
}
}
return -1;
}
//二分查找的递归实现
public static int 二分查找递归(int []arr,int key,int start,int end){
int mid=(start+end)/2;
if(arr[mid]==key){
return mid;
}
//相等
if(start>=end){
return -1;
}else if(key>arr[mid]){
return 二分查找递归(arr,key,mid+1,end);
}else if(key<arr[mid]){
return 二分查找递归(arr,key,start,mid-1);
}
return -1;
}
public static int 斐波那契数列(int n) {
if(n==0){
return 0;
}
if(n==1||n==2){
return 1;
}
int res=0;
int nums1=1,nums2=1;
for(int i=3;i<=n;i++){
res=nums1+nums2;
nums1=nums2;
nums2=res;
}
return res;
}
}
二分查找(递归、非递归、斐波那契数列)
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转载自blog.csdn.net/wenyimutouren/article/details/82251010
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