https://leetcode-cn.com/problems/longest-substring-without-repeating-characters/
description:
Given a string, you find out which does not contain a repeated character longest substring length.
Examples:
Input: "pwwkew"
Output: 3
Explanation: Because the longest substring without repeated characters is "wke", its length is 3.
Please note that your answer must be the length of the substring, "pwke" is a subsequence, not a substring.
package com.example.myapp.leetcode;
import org.junit.Assert;
import org.junit.Test;
import java.util.Collections;
import java.util.Comparator;
import java.util.HashSet;
/**
* Created by mike.
* Created on 2020/4/21.
*/
public class Code_lengthOfLongestSubstr {
@Test
public void test() {
Assert.assertEquals(3, lenghtOfLongestSubstr("abcabcbb"));
Assert.assertEquals(1, lenghtOfLongestSubstr("bbbbbb"));
Assert.assertEquals(3, lenghtOfLongestSubstr("pwwkew"));
Assert.assertEquals(1, lenghtOfLongestSubstr("a"));
Assert.assertEquals(0, lenghtOfLongestSubstr(""));
Assert.assertEquals(5, lenghtOfLongestSubstr("fanyl"));
Assert.assertEquals(6, lenghtOfLongestSubstr("java9832"));
Assert.assertEquals(7, lenghtOfLongestSubstr("beautiful"));
}
private int lenghtOfLongestSubstr(String s) {
int maxLength = 0;
if (s == null || s.length() == 0) {
System.out.println(maxLength + "aaaa");
return maxLength;
}
int startIndex = 0;
int endIndex = 0;
int length = s.length();
// length = 8
HashSet<Character> set = new HashSet<>();
while (startIndex < length && endIndex < length && startIndex <= endIndex) {
// endIndex = 0 c = a
char c = s.charAt(endIndex);
if (!set.contains(c)) {
// 不包含 set = a
set.add(c);
// endIndex = 1 ---- endIndex = 3
endIndex++;
} else {
// 包含
if (endIndex - startIndex > maxLength) {
maxLength = endIndex - startIndex;
}
// maxLength = 3
set.remove(s.charAt(startIndex));
// set bc startIndex = 1 c 2
startIndex++;
}
}
if (endIndex - startIndex > maxLength) {
maxLength = endIndex - startIndex;
}
System.out.println(maxLength);
return maxLength;
}
}
Output result:
3
1
3
1
0aaaa
5
6
7
