ZOJ2417 Lowest Bit 2017-04-18 20:53 38人阅读 评论(0) 收藏

Lowest Bit

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Time Limit: 2 Seconds      Memory Limit: 65536 KB

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Given an positive integer A (1 <= A <= 100), output the lowest bit of A.

For example, given A = 26, we can write A in binary form as 11010, so the lowest bit of A is 10, so the output should be 2.

Another example goes like this: given A = 88, we can write A in binary form as 1011000, so the lowest bit of A is 1000, so the output should be 8.

Input

Each line of input contains only an integer A (1 <= A <= 100). A line containing "0" indicates the end of input, and this line is not a part of the input data.

Output

For each A in the input, output a line containing only its lowest bit.

Sample Input

26

88

0

Sample Output

2

8

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题目的意思是给出一个n，求出n化为2进制后从低位开始第一个1代表的数

思路：无

AC代码1：化成2进制

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <queue>
#include <set>
#include <stack>
#include <map>
#include <functional>
#include <bitset>
#include <string>

using namespace std;

#define LL long long
#define INF 0x3f3f3f3f

int main()
{
    int n;
    int a[100];
    while(~scanf("%d",&n)&&n)
    {
        int len=0;
        while(n)
        {
            a[len++]=n%2;
            n/=2;
        }
        int ans=1;
        for(int i=0;i<len;i++)
        {
            if(!a[i]) ans*=2;
            else break;
        }
        printf("%d\n",ans);
    }
    return 0;
}

AC代码2：利用计算机补码快速算，树状数组原理

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <queue>
#include <set>
#include <stack>
#include <map>
#include <functional>
#include <bitset>
#include <string>

using namespace std;

#define LL long long
#define INF 0x3f3f3f3f

int lowbit(int x)
{
return x&-x;
}

int main()
{
    int n;
    while(~scanf("%d",&n)&&n)
    {
        printf("%d\n",lowbit(n));
    }
    return 0;
}