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class Solution {
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  Random random;
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  int[] origin;
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  public Solution(int[] nums) {
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    random = new Random();
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    origin = nums;
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  }
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  public int pick(int target) {
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    while (true) {
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      int idx = random.nextInt(origin.length);
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      if (origin[idx] == target) {
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        return idx;
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      }
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    }
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  }
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}