查找-二分查找

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文本：

//二分查找
//非递归实现
public static int binarySearch(int []arr,int target){
        int low=0;
        int hight=arr.length-1;
        int mid;
        while(low<=hight){
            mid=(low+hight)/2;
            if(arr[mid]==target){
                return mid+1;
            }else if(arr[mid]<target){
               low=mid+1;
            }else{
                hight=mid-1;
            }
       }
       return -1;
}



//递归实现：
public static int binarySearch(int []arr,int target,int low,int hight){
        if(low<=hight){
            int mid=(low+hight)/2;
            if(target==arr[mid]){
                return mid+1;
            }
            else if(target>arr[mid]){
                return binarySearch(arr,target,mid+1,hight);
            }else{
                return binarySearch(arr,target,low,mid-1);
            }
        }
        return -1;
}