LeetCode 398. 随机数索引

我的解题

#include <bits/stdc++.h>
using namespace std;

class Solution
{
    vector<int> &m_nums;
    size_t m_len;
public:
    /** @param head The linked list's head.
     Note that the head is guaranteed to be not null, so it contains at least one node. */
    Solution(vector<int> &nums) :
                    m_nums { nums }, m_len { nums.size() }
    {

    }

    int pick(int target)
    {
        int res = 0;
        int k = 1;
        for (int i = 0; i < m_len; ++i)
        {
            int val = m_nums[i];
            if (val == target)
            {
                if (rand() % k == 0)
                {
                    res = i;
                }
                ++k;
            }
        }
        return res;
    }
};

/**
 * Your Solution object will be instantiated and called as such:
 * Solution* obj = new Solution(head);
 * int param_1 = obj->getRandom();
 */

int main()
{

}
// g++ test.cpp --std=c++11 -pedantic -Wall -Wextra