STD函数返回子序列开始的第一个迭代器

#include <iostream>
#include <algorithm>
#include <vector>

int main() {
    std::vector<int> sequence = {1, 2, 3, 4, 5, 6, 7, 8, 9};
    std::vector<int> subsequence = {4, 5, 6};

    auto it = std::find(sequence.begin(), sequence.end(), subsequence.front());
    while (it != sequence.end()) {
        if (std::equal(it, it + subsequence.size(), subsequence.begin())) {
            break;
        }
        it = std::find(std::next(it), sequence.end(), subsequence.front());
    }

    if (it != sequence.end()) {
        std::cout << "子序列起始位置的迭代器：" << *it << std::endl;
    } else {
        std::cout << "未找到子序列" << std::endl;
    }

    return 0;
}