LeetCode 3. Longest Substring Without Repeating

Posted 2020-06-13

鏍囩锛?/p>

 

棰樼洰锛?/p>

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.

 

鎬濊矾锛?/p>

鐢ㄤ竴涓猰ap瀛樻斁瀛楃鍑虹幇鐨刾osition锛涚敤涓や釜鎸囬拡begin,end鎸囧悜substr鐨勯鏈紱閬囧埌鐩稿悓瀛楃鏃跺皢begin绉诲埌璇ュ瓧绗︿箣鍓嶅嚭鐜扮殑鍚庝竴浣嶇疆锛屽苟鏇存柊璇ュ瓧绗︾殑position銆?/p>

 

浠ｇ爜锛欳++ :

class Solution {
public:
    int lengthOfLongestSubstring(string s) {
        if (s.length() <= 1)
            return s.length();
        
        int begin = 0;
        int end = 0;
        map<char,int> mapping;
        int solve = 0;
        
        mapping[s[0]] = 0;
        while (end < s.length() - 1) {
            end++;
           if (mapping.find(s[end]) != mapping.end()) {
                int gap = end - begin;
                if (gap > solve)
                    solve = gap;
                begin = mapping[s[end]] + 1 > begin ? mapping[s[end]] + 1 : begin;
                mapping[s[end]] = end;
            }
            else
                mapping[s[end]] = end;
        }
        int gap = end - begin + 1;
        if (gap > solve)
            solve = gap;
        return solve;
    }
};