Question

How to find all possible N combinations from a vector of numbers in C++

Answer 1

#include <iostream>
#include <vector>

void generateCombinations(std::vector<int>& vec, std::vector<int>& temp, int start, int n) {
    if (n == 0) {
        for (int i = 0; i < temp.size(); i++) {
            std::cout << temp[i] << " ";
        }
        std::cout << "\n";
        return;
    }
    
    for (int i = start; i <= vec.size() - n; i++) {
        temp.push_back(vec[i]);
        generateCombinations(vec, temp, i + 1, n - 1);
        temp.pop_back();
    }
}

int main() {
    std::vector <int> vec { 3, 9, 0, 4, 7, 6 };
    std::vector<int> temp;
    int n = 2;
    
    generateCombinations(vec, temp, 0, n);
}





/*
run:

3 9 
3 0 
3 4 
3 7 
3 6 
9 0 
9 4 
9 7 
9 6 
0 4 
0 7 
0 6 
4 7 
4 6 
7 6 

*/

 

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