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class Solution {
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  public boolean isAlienSorted(String[] words, String order) {
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    int val = 1;
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    int[] alp = new int[26];
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    for (int i = 0; i < order.length(); i++) {
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      alp[order.charAt(i) - 'a'] = val;
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      val++;
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    }
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    int flag =
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        0; // if second string is shorter than first then this will be used to check if second is a
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    // subset of first starting from the beginning
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    for (int i = 0; i < words.length - 1; i++) {
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      flag = 0;
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      for (int j = 0; j < words[i].length() && j < words[i + 1].length(); j++) {
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        if (words[i].charAt(j) == words[i + 1].charAt(j)) {
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          continue;
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        }
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        if (alp[words[i].charAt(j) - 'a'] > alp[words[i + 1].charAt(j) - 'a']) {
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          return false;
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        } else if (alp[words[i].charAt(j) - 'a'] < alp[words[i + 1].charAt(j) - 'a']) {
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          flag = 1;
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          break;
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        }
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      }
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      if (flag == 0 && words[i].length() > words[i + 1].length()) {
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        return false; // if second word is sub string of first word starting from the beginning,
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        // return false.
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      }
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    }
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    return true;
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  }
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}