【经典问题】遍历得到数组的所有子序列（C++/python）

咒法师无翅鱼2024-07-24 22:10

为实现遍历所有子序列 ，C++递归函数的模板：

cpp 复制代码

#include <iostream>
#include <vector>

void Subsequence(std::vector<int>& nums, std::vector<int>& subseq, int start, int k) {
    if (subseq.size() == k) {
        //此时subseq就是一个符合要求的子序列，可进行相应操作
        return;
    }

    for (int i = start; i < nums.size(); ++i) {
        subseq.push_back(nums[i]);
        Subsequence(nums, subseq, i + 1, k);//递归调用
        subseq.pop_back();
    }
}

**C++实战例题：**实现打印所有子序列

cpp 复制代码

#include <iostream>
#include <vector>

// 打印子序列
void printSubsequence(std::vector<int>& nums, std::vector<int>& subseq, int start, int k) {
    if (subseq.size() == k) {
        for (int num : subseq) {
            std::cout << num << " ";
        }
        std::cout << std::endl;
        return;
    }

    for (int i = start; i < nums.size(); ++i) {
        subseq.push_back(nums[i]);
        printSubsequence(nums, subseq, i + 1, k);
        subseq.pop_back();
    }
}

// 主函数
int main() {
    std::vector<int> nums = {1, 2, 3, 4, 5};
    int k = 3;
    std::vector<int> subseq;
    printSubsequence(nums, subseq, 0, k);
    return 0;
}

python

cpp 复制代码

import itertools

def get_subsequences(arr, k):
    return list(itertools.combinations(arr, k))

arr = [1, 2, 3, 4, 5]
k = 3
print(get_subsequences(arr, k))

~希望对你有帮助~