NYOJ 412(bitset)

 

Same binary weight

时间限制：300 ms | 内存限制：65535 KB

难度：3

 

描述

The binary weight of a positive integer is the number of 1's in its binary representation.for example,the decmial number 1 has a binary weight of 1,and the decimal number 1717 (which is 11010110101 in binary) has a binary weight of 7.Give a positive integer N,return the smallest integer greater than N that has the same binary weight as N.N will be between 1 and 1000000000,inclusive,the result is guaranteed to fit in a signed 32-bit interget.

 

输入

The input has multicases and each case contains a integer N.

输出

For each case,output the smallest integer greater than N that has the same binary weight as N.

样例输入

1717
4
7
12
555555

样例输出

1718
8
11
17
555557

//第一个01，变为10,1的右边有n个1，把1变为0，再次把 右边的n为0变为1，答案为所求 
#include <iostream>
#include <bitset>
using namespace std;

int main()
{
    int i,j,k;
    int num;
    while(cin>>num)
    {
        bitset <32> Q;
        i=0;
        while(num>0)//大于0，更安全 
        {
            if(num&1)
                Q.set(i);//默认设置为1 
            num/=2;
            i++;
        }
        for(j=0;j<i;j++)
        {
            if(Q.test(j)&&!Q.test(j+1))//test()函数返回在pos上的位的值。
            {
                Q.flip(j);
                Q.flip(j+1);
                break;
            }
        }
        int count=0;
        for(i=0;i<j;i++)
        {
            if(Q.test(i)) 
            {
                count++;
                Q.flip(i);
            }
        }
        for(i=0;i<count;i++)
            Q.flip(i);
        //printf("%u\n",Q.to_ulong());
        cout<<Q.to_ulong()<<endl;
    }
    return 0;
}