1
class Solution {
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  public long smallestNumber(long num) {
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    if (num == 0) {
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      return 0;
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    }
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    boolean isNegative = num < 0;
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    num = num < 0 ? num * -1 : num;
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    char[] c = String.valueOf(num).toCharArray();
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    Arrays.sort(c);
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    String str;
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    if (!isNegative) {
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      int non = 0;
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      // if not negative we need to find out the first non-leading zero then swap with first zero
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      for (; non < c.length; non++) {
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        if (c[non] != '0') {
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          break;
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        }
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      }
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      char temp = c[non];
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      c[non] = c[0];
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      c[0] = temp;
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      str = new String(c);
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    } else {
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      str = new String(c);
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      StringBuilder sb = new StringBuilder(str);
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      str = "-".concat(sb.reverse().toString());
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    }
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    return Long.valueOf(str);
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  }
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}