Bulls and Cows LeetCode solution in Java

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class Solution {
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  public String getHint(String secret, String guess) {
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    int bulls = 0, cows = 0;
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    int[] secretFreq = new int[10], guessFreq = new int[10];
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    for (int i = 0; i < secret.length(); i++) {
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      char s = secret.charAt(i);
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      char g = guess.charAt(i);
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      if (s == g) bulls++;
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      else {
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        secretFreq[s - '0']++;
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        guessFreq[g - '0']++;
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      }
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    }
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    for (int i = 0; i < 10; i++) {
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      cows += Math.min(secretFreq[i], guessFreq[i]);
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    }
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    return bulls + "A" + cows + "B";
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  }
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}
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// TC: O(n), SC: O(1)