单选题库

int find_max(const vector<int>& nums) {
    if (nums.empty()) {
        throw invalid_argument("输入数组不能为空");
    }
 
    int max_value = nums[0];
    for (int num : nums) {
        if (num > max_value) {
            max_value = num;
        }
    }
    return max_value;
}

int find_max_recursive(const vector<int>& nums, int left, int right) {
    if (left == right)
        return nums[left];
 
    int mid = left + (right - left) / 2;
    int left_max = find_max_recursive(nums, left, mid);
    int right_max = find_max_recursive(nums, mid + 1, right);
 
    return max(left_max, right_max);
}
 
int find_max(const vector<int>& nums) {
    if (nums.empty()) {
        throw invalid_argument("输入数组不能为空");
    }
    return find_max_recursive(nums, 0, nums.size() - 1);
}

bool is_prime(int n) {
    if (n <= 1) return false;
 
    int finish_number = static_cast<int>(sqrt(n)) + 1;
    for (int i = 2; i < finish_number; ++i) {
        if (n % i == 0)
            return false;
    }
    return true;
}

int gcd0(int big, int small) {
    if (big < small) {
        swap(big, small);
    }
    if (big % small == 0) {
        return small;
    }
    return gcd0(small, big % small);
}
 
int gcd1(int big, int small) {
    if (big < small) {
        swap(big, small);
    }
    for (int i = small; i >= 1; --i) {
        if (big % i == 0 && small % i == 0)
            return i;
    }
    return 1;
}