SwappingDigits.java

SwappingDigits.java

import java.util.Collections;
import java.util.TreeSet;

public class SwappingDigits {

  public String minNumber(String num) {
    TreeSet<String> results = new TreeSet<String>();
    results.add(num);
    int n = num.length();
    for (int i = 0; i < n; i++) {
      for (int j = i+1; j < n; j++) {
          char[] arr = num.toCharArray();
          arr[i]=num.charAt(j);
          arr[j]=num.charAt(i);
          if (arr[0]!='0') {
          results.add(new String(arr));
        }
      }
    }
    return Collections.min(results);
  }
}