78 lines
2.5 KiB
Java
78 lines
2.5 KiB
Java
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/*
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Given a string, find the longest substrings without repeating characters. Iterate through the given string, find the longest maximum substrings.
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*/
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import java.util.HashSet;
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import java.util.Set;
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public class MyLongestSubstr
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{
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private Set<String> subStrList = new HashSet<String>();
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private int finalSubStrSize = 0;
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public Set<String> getLongestSubstr(String input)
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{
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//reset instance variables
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subStrList.clear();
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finalSubStrSize = 0;
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// have a boolean flag on each character ascii value
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boolean[] flag = new boolean[256];
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int j = 0;
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char[] inputCharArr = input.toCharArray();
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for (int i = 0; i < inputCharArr.length; i++)
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{
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char c = inputCharArr[i];
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if (flag[c])
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{
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extractSubString(inputCharArr,j,i);
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for (int k = j; k < i; k++)
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{
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if (inputCharArr[k] == c)
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{
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j = k + 1;
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break;
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}
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flag[inputCharArr[k]] = false;
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}
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}
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else
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{
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flag[c] = true;
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}
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}
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extractSubString(inputCharArr,j,inputCharArr.length);
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return subStrList;
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}
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private String extractSubString(char[] inputArr, int start, int end)
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{
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StringBuilder sb = new StringBuilder();
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for(int i=start; i<end; i++)
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{
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sb.append(inputArr[i]);
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}
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String subStr = sb.toString();
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if(subStr.length() > finalSubStrSize)
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{
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finalSubStrSize = subStr.length();
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subStrList.clear();
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subStrList.add(subStr);
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}
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else if(subStr.length() == finalSubStrSize)
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{
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subStrList.add(subStr);
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}
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return sb.toString();
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}
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public static void main(String a[])
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{
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MyLongestSubstr mls = new MyLongestSubstr();
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System.out.println(mls.getLongestSubstr("java2novice"));
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System.out.println(mls.getLongestSubstr("java_language_is_sweet"));
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System.out.println(mls.getLongestSubstr("java_java_java_java"));
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System.out.println(mls.getLongestSubstr("abcabcbb"));
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}
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}
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