c++ - 生成汉明距离t内的所有位序列

给定位v的位 vector ，请计算汉明距离为1的位的集合与v，然后为距离2，直至输入参数t。

因此对于

011  I should get
~~~
111
001
010
~~~ -> 3 choose 1 in number
101
000
110
~~~ -> 3 choose 2
100
~~~ -> 3 choose 3

如何有效地计算呢？ vector 并不总是尺寸为3，例如可能是6。这将在我的真实代码中运行很多次，因此也将欢迎提高效率(即使付出更多的内存)。

我的尝试:

#include <iostream>
#include <vector>

void print(const std::vector<char>& v, const int idx, const char new_bit)
{
    for(size_t i = 0; i < v.size(); ++i)
        if(i != idx)
            std::cout << (int)v[i] << " ";
        else
            std::cout << (int)new_bit << " ";
    std::cout << std::endl;
}

void find_near_hamming_dist(const std::vector<char>& v, const int t)
{
    // if t == 1
    for(size_t i = 0; i < v.size(); ++i)
    {
        print(v, i, v[i] ^ 1);
    }

    // I would like to produce t == 2
    // only after ALL the t == 1 results are reported
    /* how to? */
}

int main()
{
    std::vector<char> v = {0, 1, 1};
    find_near_hamming_dist(v, 1);
    return 0;
}

输出:

MacBook-Pro:hammingDist gsamaras$ g++ -Wall -std=c++0x hammingDist.cpp -o ham
MacBook-Pro:hammingDist gsamaras$ ./ham
1 1 1
0 0 1
0 1 0

最佳答案

#include <stdio.h>
#include <stdint.h>
#include <string.h>

void magic(char* str, int i, int changesLeft) {
        if (changesLeft == 0) {
                printf("%s\n", str);
                return;
        }
        if (i < 0) return;
        // flip current bit
        str[i] = str[i] == '0' ? '1' : '0';
        magic(str, i-1, changesLeft-1);
        // or don't flip it (flip it again to undo)
        str[i] = str[i] == '0' ? '1' : '0';
        magic(str, i-1, changesLeft);
}

int main(void) {
        char str[] = "011";
        printf("%s\n", str);
        size_t len = strlen(str);
        size_t maxDistance = len;
        for (size_t i = 1 ; i <= maxDistance ; ++i) {
                printf("Computing for distance %d\n", i);
                magic(str, len-1, i);
                printf("----------------\n");
        }
        return 0;
}

输出:

MacBook-Pro:hammingDist gsamaras$ nano kastrinis.cpp
MacBook-Pro:hammingDist gsamaras$ g++ -Wall kastrinis.cpp
MacBook-Pro:hammingDist gsamaras$ ./a.out
011
Computing for distance 1
010
001
111
----------------
Computing for distance 2
000
110
101
----------------
Computing for distance 3
100
----------------

关于c++ - 生成汉明距离t内的所有位序列，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/40813022/