1110: nearest common ancestor (function topic)

Title Description

As shown in the figure above , From positive integers 1, 2, 3, ... It forms an infinite binary tree . From a node to the root node  
spot （ The number is 1 The node of ） There is a unique path , For instance from 10 The path to the root node is (10, 5, 2, 1), 
from 4 The path to the root node is (4, 2, 1), All nodes on the path from the node to the root node are called the ancestors of the node . The problem now is , Given x and y, seek x and y The most recent common ancestor of , such as ,10 and 4 The most recent common ancestor is 2,10 and 5 Our nearest common ancestor is 5. 
Define recursive functions  
int common(int x, int y) 
{ 
If x==y, return x; 
If x>y, seek x/2 And y The common ancestor of ; 
otherwise , seek x And y/2 The common ancestor of ; 
}

Input

There is only one line of input , Including two positive integers x and y, Neither of these positive integers is greater than 1000.

Output

The output has only one positive integer , namely x and y The most recent common ancestor of .

The sample input  Copy

10 4

Sample output  Copy

2

Code ：

#include<stdio.h>
int common(int x,int y)
{
    if(x==y)
    return x;
    else if(x>y)
    common(x/2,y);
    else common(x,y/2);
}
int main()
{
     int x,y,m;
     scanf("%d%d",&x,&y);
     m=common(x,y);
     printf("%d",m);
}

Operation diagram ：

  What has been learned ：

  From this question I know , The defined function can also be called in the definition function module , Let the originally linear function form a circle through this ingenious call , So as to achieve the purpose of circulation .

This design is too clever , cattle B cattle B！