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| import java.util.HashSet;
import java.util.Set;
public class MyLongestSubstr {
private Set<String> subStrList = new HashSet<String>();
private int finalSubStrSize = 0;
public Set<String> getLongestSubstr(String input) {
// reset instance variables
subStrList.clear();
finalSubStrSize = 0;
// have a boolean flag on each character ascii value
boolean[] flag = new boolean[256];
int j = 0;
char[] inputCharArr = input.toCharArray();
for (int i = 0; i < inputCharArr.length; i++) {
char c = inputCharArr[i];
if (flag[c]) {
extractSubString(inputCharArr, j, i);
for (int k = j; k < i; k++) {
if (inputCharArr[k] == c) {
j = k + 1;
break;
}
flag[inputCharArr[k]] = false;
}
} else {
flag[c] = true;
}
}
extractSubString(inputCharArr, j, inputCharArr.length);
return subStrList;
}
private String extractSubString(char[] inputArr, int start, int end) {
StringBuilder sb = new StringBuilder();
for (int i = start; i < end; i++) {
sb.append(inputArr[i]);
}
String subStr = sb.toString();
if (subStr.length() > finalSubStrSize) {
finalSubStrSize = subStr.length();
subStrList.clear();
subStrList.add(subStr);
} else if (subStr.length() == finalSubStrSize) {
subStrList.add(subStr);
}
return sb.toString();
}
public static void main(String a[]){
MyLongestSubstr mls = new MyLongestSubstr();
System.out.println(mls.getLongestSubstr("java2novice"));
System.out.println(mls.getLongestSubstr("java_language_is_sweet"));
System.out.println(mls.getLongestSubstr("java_java_java_java"));
System.out.println(mls.getLongestSubstr("abcabcbb"));
}
}
|