Longest Substring Without Repeating Characters (返回最长无字符重复的子串长度)

最新推荐文章于 2024-01-25 23:17:44 发布

原创最新推荐文章于 2024-01-25 23:17:44 发布 · 1.1k 阅读

0 ·

CC 4.0 BY-SA版权

LetCode 专栏收录该内容

4 篇文章

订阅专栏

本文介绍了一个算法，用于在给定字符串中找到最长的不包含重复字符的子串。通过遍历字符串并使用哈希表跟踪字符的最近出现位置，该算法有效地解决了这一问题，提供了一个在时间和空间效率上的解决方案。

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.

public class Solution {
	// 没有重复的最长子串的长度
	public int lengthOfLongestSubstring(String s) {
		int[] hash=new int[256];
		int len = s.length();
		int i=0;
		int j=0;
		int maxLen = 0;
		int tempLen = 0;
		int tIndex = 0;
		char[] arr = s.toCharArray();
		for(i=0;i<256;i++){
			hash[i]=-1;
		}
		for (i = 0; i < len; i++) {
			// 复杂度为n
			int ic=(int)arr[i];
			if (hash[ic]==-1) {
				hash[ic]=i;
				tempLen++;
			} else {
				// 获取重复出现字符串的最小索引tIndex
				tIndex = hash[ic];
				// 当出现重复时,需要清空已有的标记
				 for (j = 0; j < 256; j++) {
				     hash[j]=-1;
				 }
				// 因为i跳过本次循环后会自动+1
				i = tIndex;
				tempLen = 0;
			}
			maxLen = maxLen > tempLen ? maxLen : tempLen;
		}
		return maxLen;
	}

	public static void main(String args[]) {
		Solution s = new Solution();
//		int l = s.lengthOfLongestSubstring("wlrbbmqbhcdarzowkkyhiddqscdxrjmowfrxsjybldbefsarcbynecdyggxxpklorellnmpapqfwkhopkmco");
//		int l = s.lengthOfLongestSubstring("hchzvfrkmlnozjk");
		int l = s.lengthOfLongestSubstring("qopubjguxhxdipfzwswybgfylqvjzhar");
		System.out.print(l);
	}
}