[LeetCode]Q3. Longest Substring Without Repeating Characters，leetcoderepeating

[LeetCode]Q3. Longest Substring Without Repeating Characters，leetcoderepeating

Problem Description

Given a string, find the length of the longest substring without repeating characters. For example, the longest substring without repeating letters for “abcabcbb” is “abc”, which the length is 3. For “bbbbb” the longest substring is “b”, with the length of 1.
[https://leetcode.com/problems/longest-substring-without-repeating-characters/]

思路

把词库里所有的字母都遍历一遍，在字符串中算出每个字符与前一个相同字符的距离。之后利用这个距离数组，计算最长无重复字符字符串。

代码

package Q3;

public class Solution {
    public static int lengthOfLongestSubstring(String s) {
        if (s.length() < 1)
            return 0;
        return GetMaxLen(FindLen(s));

    }

    public static int GetMaxLen(int[] SameLen) {
        int max = 0;
        int newMax = 0;
        for (int i = 0; i < SameLen.length; i++) {
            if (SameLen[i] == 0)
                newMax++;
            else if (SameLen[i] < newMax)
                newMax = SameLen[i];
            else if (SameLen[i] > newMax)
                newMax++;
            if (newMax > max)
                max = newMax;

        }

        return max;
    }

    public static int[] FindLen(String s) {
        int SameLen[] = new int[s.length()];
        for (int i = 0; i < SameLen.length; i++) {
            SameLen[i] = 0;
        }
        String tmp = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~ ";
        System.out.print(tmp.length());
        for (int i = 0; i < tmp.length(); i++) {
            char a = tmp.charAt(i);
            int k = 1;
            int first = 1;
            for (int j = 0; j < s.length(); j++) {
                if (s.charAt(j) == a && first == 1) {
                    SameLen[j] = 0;
                    k = 1;
                    first = 0;
                } else {
                    if (s.charAt(j) == a) {
                        SameLen[j] = k;
                        k = 1;
                    } else {
                        k++;
                    }
                }
            }
        }

        return SameLen;
    }

    public static void main(String[] args) {

        System.out.print(lengthOfLongestSubstring("asd"));

    }

}