Longest Substring Without Repeating Characters
Total Accepted: 152787 Total
Submissions: 687012 Difficulty: Medium
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",244)">"b",with the length of 1.
Given "pwwkew",244)">"wke",with the length of 3. Note that the answer must be a substring, "pwke" is
a subsequence and not a substring.
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思路：
保护1个HashMap存储每一个字符的位置；两个指针i,j，保护最长子串的范围。
java code:
public class Solution {
public int lengthOfLongestSubstring(String s) {
if(s==null || s.length()==0) return 0;
Map<Character,Integer> map = new HashMap<Character,Integer>();
int max = 0;
for(int i=0,j=0;i<s.length();i++) {
char c = s.charAt(i);
if(map.containsKey(c)) {
j = Math.max(j,map.get(c)+1);
}
map.put(c,i);
max = Math.max(max,i-j+1);
}
return max;
}
}
