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class Solution {
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  public int myAtoi(String s) {
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    long n = 0;
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    int i = 0, a = 0;
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    s = s.trim();
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    if (s.length() == 0) return 0;
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    if (s.charAt(i) == '+' || s.charAt(i) == '-') a = 1;
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    while (a < s.length())
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      if (s.charAt(a) == '0') a++;
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      else break;
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    for (i = a; i < a + 11 && i < s.length(); i++) {
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      if (s.charAt(i) >= '0' && s.charAt(i) <= '9') n = n * 10 + (int) (s.charAt(i) - '0');
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      else break;
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    }
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    if (s.charAt(0) == '-') n = -n;
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    if (n > 2147483647) n = 2147483647;
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    if (n < -2147483648) n = -2147483648;
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    return (int) n;
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  }
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}