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class Solution {
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 public:
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  bool validUtf8(vector<int> &data) {
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    int n = data.size();
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    int count = 0;
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    for (int i = 0; i < n; i++) {
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      int ele = data[i];
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      if (!count) {
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        // if the first 3 bits are 110, then the next byte is part of the
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        // current UTF-8 character
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        if ((ele >> 5) == 0b110) count = 1;
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        // if the first 4 bits are 1110, then the next 2 bytes are part of the
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        // current UTF-8 character
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        else if ((ele >> 4) == 0b1110)
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          count = 2;
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        // if the first 5 bits are 11110, then the next 3 bytes are part of the
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        // current UTF-8 character
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        else if ((ele >> 3) == 0b11110)
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          count = 3;
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        // if the first bit is 1, then return false
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        else if ((ele >> 7))
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          return false;
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      } else {
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        // if the first 2 bits are not 10, then return false
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        if ((ele >> 6) != 0b10) return false;
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        count--;
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      }
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    }
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    return (count == 0);
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  }
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};