首页 > 代码库 > Lowbit Sum 规律

Lowbit Sum 规律

Lowbit Sum

Time Limit: 2000/1000MS (Java/Others) Memory Limit: 128000/64000KB (Java/Others)
SubmitStatus

Problem Description

long long ans = 0;
for(int i = 1; i <= n; i ++)
    ans += lowbit(i)
lowbit(i)的意思是将i转化成二进制数之后,只保留最低位的1及其后面的0,截断前面的内容,然后再转成10进制数
比如lowbit(7),7的二进制位是111,lowbit(7) = 1
6 = 110(2),lowbit(6) = 2,同理lowbit(4) = 4,lowbit(12) = 4,lowbit(2) = 2,lowbit(8) = 8

每输入一个n,求ans

Input

多组数据,每组数据一个n(1 <= n <= 10^9)

Output

每组数据输出一行,对应的ans

Sample Input

123

Sample Output

134


 1 #include <iostream> 2 #include <stdio.h> 3 #include <string.h> 4 #include <math.h> 5 #include <algorithm> 6 using namespace std; 7 #define ll long long 8 ll solve(int x) 9 {10     if(x==0)return 0;11     return ((x+1)>>1)+(solve(x/2)<<1);12 }13 int main()14 {15     int n;16     while(~scanf("%d",&n))17     {18         printf("%lld\n",solve(n));19     }20 }
View Code