第21356题 单选题
以下C++实现的求最长上升子序列长度的LIS函数的时间复杂度为?
#define INT_MIN (-1000)
int LIS(vector<int> & nums) {
    int n = nums.size();
    vector<int> tail;
    tail.push_back(INT_MIN);
    for (int i = 0; i < n; i++) {
        int x = nums[i], l = 0, r = tail.size();
        while (l < r) {
            int mid = (l + r) / 2;
            if (tail[mid] < x)
                l = mid + 1;
            else
                r = mid;
        }
        if (r == tail.size())
            tail.push_back(x);
        else
            tail[r] = x;
    }
    return tail.size() - 1;
A

O(log n)

B

O(n)

C

O(n log n)

D

O(n²)

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