static string factorial(const size_t n) {

auto start = std::to_string(n);

string &result = factorialImpl(start, 2, n);

std::reverse(result.begin(), result.end());

std::cout << result;

return result;

}

//大数乘法 将得到两者相乘的数据实现

static string big_number_multiply(const string &first, const size_t second) {

assert(not first.empty());

size_t t = 0;

const size_t first_len = first.size();

string result;

result.reserve(first_len + 10);

for (int i = 0; i < first_len || t; i++) {

if (i < first.size()) {

t += (static_cast<size_t>(first.at(i) - '0')) * second;

}

char getChar = t % 10 + '0';

result.push_back(getChar);

t /= 10;

}

return result;

}

static string &factorialImpl(string &first, size_t second, size_t target) {

if (second >= target) return first;

first = big_number_multiply(first, second);

return factorialImpl(first, second + 1, target);

}

// Dynamic::package();

// TreeAlgo::run();

// Dynamic::winner();

// Dynamic::minimum_manipulate();

//ArrayAlgo::not_exists_num();

//StringAglo::find_longest_not_repeat_sub();

//StringAglo::string_replace();

//StringAglo::boolean_expression();

//ArrayAlgo::change_array_data();

//ArrayAlgo::JosephProblem();

/*ArrayAlgo::longestTotalArray();*/

//ArrayAlgo::longestTotalArray();

//LeetCode::medium_34();

//LeetCode::medium_33();

//LeetCode::findPeakElement();

//LeetCode::medium_74();

//LeetCode::findMin();

//LeetCode::deleteDuplicatesFromList();

//LeetCode::three_num();

//LeetCode::backspaceCompare/*(*/);

// LeetCode::findAnagrams();

//LeetCode::numSubarrayProductLessThanK();

//LeetCode200::shortestPathBinaryMatrix();

Offer::containsNearbyAlmostDuplicate();

ArrayAlgo::containsNearbyDuplicate();