Leetcode 398 Solution

This article provides solution to leetcode question 398 (random-pick-index)
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https://leetcode.com/problems/random-pick-index

Solution

class Solution {
    vector<int> m_nums;

public:
    Solution(vector<int> nums) {
        m_nums = nums;
    }

    int pick(int target) {
        int cnt = 0;
        int res = -1;

        for (int i = 0; i < m_nums.size(); i++)
        {
            if (m_nums[i] != target)
                continue;

            cnt++;

            if (rand() % cnt == 0)
                res = i;
        }

        return res;
    }
};

/**
 * Your Solution object will be instantiated and called as such:
 * Solution obj = new Solution(nums);
 * int param_1 = obj.pick(target);
 */