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

 1 //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 

 2 #include <iostream>

 3 #include <bitset>

 4 using namespace std;

 5 

 6 int main()

 7 {

 8     int i,j,k;

 9     int num;

10     while(cin>>num)

11     {

12         bitset <32> Q;

13         i=0;

14         while(num>0)//大于0，更安全 

15         {

16             if(num&1)

17                 Q.set(i);//默认设置为1 

18             num/=2;

19             i++;

20         }

21         for(j=0;j<i;j++)

22         {

23             if(Q.test(j)&&!Q.test(j+1))//test()函数返回在pos上的位的值。

24             {

25                 Q.flip(j);

26                 Q.flip(j+1);

27                 break;

28             }

29         }

30         int count=0;

31         for(i=0;i<j;i++)

32         {

33             if(Q.test(i)) 

34             {

35                 count++;

36                 Q.flip(i);

37             }

38         }

39         for(i=0;i<count;i++)

40             Q.flip(i);

41         //printf("%u\n",Q.to_ulong());

42         cout<<Q.to_ulong()<<endl;

43     }

44     return 0;

45 }