打印所有子向量组合 + 问题

Print All Subvector Combinations + Issue

我正在尝试创建一个工具,让我的生活更轻松,以便根据数字加法设置配置设置列表,以指示应启用哪些功能。我使用的是 2 的幂列表,从 1 到 512 (1,2,4,8,16,32,64,128,256,512)。

手动检查并创建一个列表,列出哪些值将启用哪些功能会非常耗时,因此我尝试以编程方式进行,然后将输出保存到文件中。但是,我 运行 遇到了寻找合适解决方案的问题。

我已经阅读了 Google 中关于该主题的来自 SO 和其他编码论坛的几乎所有问题,并且所有问题都涉及线性组合。这是我能够做到的,我有这个示例代码,我修改了它,然后在以下基础上构建了我的工具:

    #include <iostream>
using std::cout;
using std::cin;
using std::endl;

// A is the array that contains the numbers
// comb is an array of size k that will hold all possible combinations
// n is the size of input array
// k is 1 less than the size of combination i.e. we want to find out 4C2 k =1
// current_k is the variable that makes us simulates k loops in a recursive function
void combinations(int A[], int comb[], int start, int n, int current_k, int k){
    int sum = 0;

    if (k < 0)
        return;

    // Base case just print all the numbers 1 at a time
    if (k == 0){
        for (int i = 0; i < n; i++)
            cout << A[i] << endl;
    }

    // current_k goes from 0 to k-1 and simulates a total of 
    // k iterations
    if (current_k < k){
        // if current_k = 0, and k = 3 (i.e. we need to find combinations of 4) 
        // then we need to leave out 3 numbers from the end because there are 3
        // more nested loops
        for (int i = start; i < n - (k - current_k); i++){
            // Store the number in the comb array and recursively call with the remaining sub-array
            comb[current_k] = A[i];
            // This will basically pass a sub array starting at index 'start' and going till n-1
            combinations(A, comb, i+1, n, current_k+1, k);
        }
    }

    else if (current_k == k){
        for (int i = start; i < n; i++){
            comb[current_k] = A[i];

            for (int j = 0; j <= k; j++){
                sum += comb[j];     
            }
            
            cout << sum << endl;
            sum = 0;
        }
    }

    else
        return;
}

int main(){
    int n;
    cout << "Enter the 'n' " << endl;
    cin >> n;
    int *A = new int[n];

    for (int i = 0; i < n; i++)
        A[i] = i+1;

    int k;
    cout << "Enter 'k'" << endl;
    cin >> k;
    int *comb = new int[k];

    combinations(A, comb, 0, n, 0, k-1);

    system("pause");
    return 0;
}

唯一的问题是我还需要 non-linear 组合。像 1+64+256 这样的东西。这是否也能够拾取这些组合?我也有一个问题,我将在 post 我的代码后解释。这是我为此使用的实际代码:

#include <iostream>
#include <vector>
#include <string>
#include "mcl.h"

using std::cout;
using std::vector;
using std::string;
using std::cin;
using std::endl;

static vector<string> results;

// A is the array that contains the numbers
// comb is an array of size k that will hold all possible combinations
// n is the size of input array
// k is 1 less than the size of combination i.e. we want to find out 4C2 k =1
// current_k is the variable that makes us simulates k loops in a recursive function
void combinations(vector<mcl> A, vector<mcl> comb, int start, int n, int current_k, int k){
    string sum;
    string sNames;
    int sCodes = 0;

    if (k < 0)
        k = 0;

    // Base case just print all the numbers 1 at a time
    if (k == 0){
        for (int i = 0; i < n; i++)
            cout << A.at(i).getCode() << " - " << A.at(i).getName() << endl;
        return;
    }

    // current_k goes from 0 to k-1 and simulates a total of 
    // k iterations
    if (current_k < k){
        // if current_k = 0, and k = 3 (i.e. we need to find combinations of 4) 
        // then we need to leave out 3 numbers from the end because there are 3
        // more nested loops
        for (int i = start; i < n - (k - current_k); i++){
            // Store the number in the comb array and recursively call with the remaining sub-array
            comb.push_back(mcl(A.at(i).getCode(),A.at(i).getName()));
            // This will basically pass a sub array starting at index 'start' and going till n-1
            combinations(A, comb, i + 1, n, current_k + 1, k);
        }
    }

    else if (current_k == k){
        for (int i = start; i < n; i++){
            comb.at(current_k-1) = A.at(i);

            for (int j = 0; j < k; j++){
                sCodes += comb.at(j).getCode();
                if (sNames != ""){
                    sNames = sNames + "," + comb.at(j).getName();
                }

                else{
                    sNames = sNames + comb.at(j).getName();
                }
            }
        }

        results.push_back(sCodes + " - " + sNames);
        sCodes = 0;
        sNames = "";
    }

    else
        return;
}

int main(){
    int k;
    vector<mcl> A,comb;

    A.push_back(mcl(1, "Light"));
    A.push_back(mcl(2, "Bright"));
    A.push_back(mcl(4, "Dark"));

    k = 2;
    

    combinations(A, comb, 0, A.size(), 0, k - 1);

    //system("cls");
    for (int i1 = 0; i1 < results.size(); i1++){
        cout << results.at(i1) << endl;
    }

    system("pause");
    return 0;
}

mcl header 和 imp 代码:

#ifndef MCL_H
#define MCL_H

#include <string>

using std::string;

class mcl{
public:
    mcl(int code, string name);

    int getCode();
    string getName();

    void setCode(int i);
    void setName(string s);

private:
    int cCode;
    string cName;
};
#endif;

小鬼:

#include "mcl.h";

mcl::mcl(int code, string name){
    cCode = code;
    cName = name;
}

int mcl::getCode(){
    return cCode;
}

string mcl::getName(){
    return cName;
}

void mcl::setCode(int i){
    cCode = i;
}

void mcl::setName(string s){
    cName = s;
}

现在正题。当我尝试测试我在代码中定义的三个 mcl objects 的组合显示时,我看到了这个输出:

Bright,Dark

,Dark

Press any key to continue . . .

正如我所看到的,如果我将 k 设置为 0,每个 object 的数据都会正确显示:

1 - Light

2 - Bright

4 - Dark

Press any key to continue . . .

我认为这个问题是由创建用于显示的结果向量的 for 循环引起的,但我不确定实际问题是什么。

关于我的预期输出示例,鉴于上面代码中的硬编码元素,这就是我试图让工具输出的内容(其中粗体是基本设置,non-bolded 是组合) :

1 - 浅色
2 - 明亮
3 - 浅色、明亮
4 - 深色
5 - 浅色、深色
6 - 明亮、黑暗
7 - 亮、亮、暗

看了一会儿你的代码;并试图了解你在组合函数中找到的这部分代码引起了我的注意:

    else if ( current_k == k ) {
        for ( int i = start; i < n; i++ ) {
            comb.at(current_k-1) = A.at(i);

            for ( int j = 0; j < k; j++ ){
                sCodes += comb.at(j).getCode();
                if ( sNames != "" ) {
                    sNames = sNames + "," + comb.at(j).getName();

                } else {
                    sNames = sNames + comb.at(j).getName();
                }
            }
        }

        results.push_back(sCodes + " - " + sNames);
        sCodes = 0;
        sNames = "";

    } else {
        return;
    }

我在这里想的是你正在经历一个双 for 循环,并且在双 for 循环完成之前你不会更新你的矢量。这是你想要的吗?或者你的意思是在内部 for 循环的每次迭代后保存? If So 那么你只需要在你的 if else 语句之后将它移动到内部 for 循环的内部,修改后的代码将如下所示:

    else if ( current_k == k ) {
        for ( int i = start; i < n; i++ ) {
            comb.at(current_k-1) = A.at(i);

            for ( int j = 0; j < k; j++ ){
                sCodes += comb.at(j).getCode();
                if ( sNames != "" ) {
                    sNames = sNames + "," + comb.at(j).getName();

                } else {
                    sNames = sNames + comb.at(j).getName();
                }

                results.push_back(sCodes + " - " + sNames);
            }
        }

        sCodes = 0;
        sNames = "";

    } else {
        return;
    }

如果这对您有任何帮助,请告诉我;不幸的是,我没有可用的时间尝试在我的 IDE 中重新创建您的代码来尝试编译、构建、运行 和调试以查看修改后版本的输出是否正确。我是从头顶视觉上做这件事的。如果我在不久的将来有空闲时间;我也许可以这样做并尝试看看我能想出什么。

因此,经过大量研究和测试后,我决定这对我的情况来说效果不佳,而且在性能方面成本太高。相反,我选择通过中介 table 的数据库内 (SQLite) 解决方案,该解决方案将以一对多关系将一个 table 中的 ID 映射到另一个 table 中的 ID。与上面示例试图通过代码处理所有代码的蛮力方法相比,更易于编码且性能非常精简。