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class Solution {
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  public int totalHammingDistance(int[] nums) {
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    int total = 0;
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    int[][] cnt = new int[2][32];
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    for (int i = 0; i < nums.length; i++) {
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      for (int j = 0; j < 32; j++) {
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        int idx = (nums[i] >> j) & 1;
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        total += cnt[idx ^ 1][j];
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        cnt[idx][j]++;
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      }
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    }
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    return total;
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  }
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}