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class Solution {
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  unordered_map<int, vector<int>> itemIndicies;
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 public:
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  Solution(vector<int> &nums) {
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    srand(time(NULL));
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    for (int i = 0; i < nums.size(); i++) {
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      if (itemIndicies.find(nums[i]) == itemIndicies.end())
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        itemIndicies[nums[i]] = {i};
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      else
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        itemIndicies[nums[i]].push_back(i);
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    }
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  }
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  int pick(int target) {
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    int size = itemIndicies[target].size();
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    int randomValue = rand() % size;
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    return itemIndicies[target][randomValue];
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  }
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};
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/**
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 * Your Solution object will be instantiated and called as such:
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 * Solution* obj = new Solution(nums);
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 * int param_1 = obj->pick(target);
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 */