Compare Strings by Frequency of the Smallest Character LeetCode solution in Java

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class Solution {
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  public int[] numSmallerByFrequency(String[] queries, String[] words) {
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    int[] ans = new int[queries.length];
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    int[] freq = new int[words.length];
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    for (int i = 0; i < words.length; i++) {
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      freq[i] = freqOfSmallest(words[i]);
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    }
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    Arrays.sort(freq);
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    int k = 0;
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    for (String query : queries) {
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      int target = freqOfSmallest(query);
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      ans[k++] = binarySearch(freq, target);
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    }
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    return ans;
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  }
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  public int freqOfSmallest(String s) {
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    int[] freq = new int[26];
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    char min = 'z';
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    for (int i = 0; i < s.length(); i++) {
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      char c = s.charAt(i);
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      freq[c - 'a'] += 1;
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      if (c < min) {
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        min = c;
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      }
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    }
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    return freq[min - 'a'];
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  }
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  public int binarySearch(int[] arr, int target) {
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    int idx = arr.length;
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    int lo = 0;
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    int hi = idx - 1;
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    int mid;
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    while (lo <= hi) {
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      mid = (lo + hi) / 2;
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      if (arr[mid] <= target) {
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        lo = mid + 1;
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      } else {
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        idx = mid;
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        hi = mid - 1;
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      }
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    }
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    return arr.length - idx;
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  }
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}