LeetCode 3. Longest Substring Without Repeating Characters

주어진 문자열에서 문자가 반복되지 않는 가장 긴 서브(sub) 문자열 찾기

#Algotithm #LeetCode


Description

Given a string, find the length of the longest substring without repeating characters.

Examples:

Given "abcabcbb", the answer is "abc", which the length is 3.

Given "bbbbb", the answer is "b", with the length of 1.

Given "pwwkew", the answer is "wke", with the length of 3. Note that the answer must be a substring, "pwke" is a subsequence and not a substring.
public class Solution {
    public int lengthOfLongestSubstring(String s) {
        
    }
}

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Solution

/**
 * 3. Longest Substring Without Repeating Characters
 *
 * @author kimtaeng
 * created on 2018. 1. 9.
 */
public class Solution {
    public int lengthOfLongestSubstring(String s) {
        int length = 0;
        int[] arr = new int[128];

        for(int idx=0; idx<arr.length; idx++) {
            arr[idx] = 0;
        }

        int position = 0;
        int inputLength = s.length();
        for (int indexOfString = 0; indexOfString < inputLength; indexOfString++) {
            int charIndex = (int) s.charAt(indexOfString);
            position = getMax(arr[charIndex], position);
            length = getMax(length, indexOfString - position + 1);
            arr[charIndex] = indexOfString + 1;
        }
        return length;
    }

    public int getMax(int a, int b) {
        return a > b ? a : b;
    }
}