JZ-073 - Longest substring without repeating characters

longest substring without repeating characters

Topic description

Input a string (contain only the characters a~z), find the length of the longest substring without repeating characters. For example, for arabcacfr, the longest substring without repeating characters is acfr and has a length of 4.

link : [the longest substring without repeating characters]()

code

import java.util.Arrays;

/**
 * 标题：最长不含重复字符的子字符串
 * 题目描述
 * 输入一个字符串（只包含 a~z 的字符），求其最长不含重复字符的子字符串的长度。例如对于 arabcacfr，最长不含重复字符的子字符串为 acfr，长度为 4。
 */
public class Jz73 {

    public int longestSubStringWithoutDuplication(String str) {
        int curLen = 0;
        int maxLen = 0;
        int[] preIndexs = new int[26];
        Arrays.fill(preIndexs, -1);
        for (int curI = 0; curI < str.length(); curI++) {
            int c = str.charAt(curI) - 'a';
            int preI = preIndexs[c];
            if (preI == -1 || curI - preI > curLen) {
                curLen++;
            } else {
                maxLen = Math.max(maxLen, curLen);
                curLen = curI - preI;
            }
            preIndexs[c] = curI;
        }
        maxLen = Math.max(maxLen, curLen);
        return maxLen;
    }

    public static void main(String[] args) {
        
    }
}

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