[递归]二的幂次方

题目描述

Every positive number can be presented by the exponential form.For example, 137 = 2^7 + 2^3 + 2^0。     Let’s present a^b by the form a(b).Then 137 is presented by 2(7)+2(3)+2(0). Since 7 = 2^2 + 2 + 2^0 and 3 = 2 + 2^0 , 137 is finally presented by 2(2(2)+2 +2(0))+2(2+2(0))+2(0).        Given a positive number n,your task is to present n with the exponential form which only contains the digits 0 and 2.

示例

输入

1315

输出

2(2(2+2(0))+2)+2(2(2+2(0)))+2(2(2)+2(0))+2+2(0)

解法

#include<iostream>
#include<cmath>
using namespace std;
void generate(int j){
    int jj = j;
    int n=0;
    if(jj==1)cout<<"2(0)";
    if(jj==2)cout<<"2";
    if(jj==3)cout<<"2+2(0)";
    if(jj==4)cout<<"2(2)";
    if(jj==5)cout<<"2(2)+2(0)";
    if(jj==6)cout<<"2(2)+2";
    if(jj==7)cout<<"2(2)+2+2(0)";
    if(jj>7){
	    if((jj&(jj-1))==0){
	    	for(int i=0;i<16;i++){
	    		if(pow(2,i)==jj){
	    			cout<<"2(";
	    			generate(i);
	    			cout<<")";
	    			return;
			}
		}
	    }
	    while((jj&(jj-1))!=0){
		jj--;
		n++;
	    }
	    generate(jj);
	    cout<<"+";
	    generate(n);  
    }
}
int main(){
    int a;
    scanf("%d",&a);
    generate(a);
    cout<<endl;
    return 0;
}