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Add Two Numbers
[Problem Link]
Description
Given a string, find the length of the longest substring without repeating characters.
Example
Input: "abcabcbb"
Output: 3
Explanation: The answer is "abc", with the length of 3.
Input: "bbbbb"
Output: 1
Explanation: The answer is "b", with the length of 1.
Input: "pwwkew"
Output: 3
Explanation: The answer is "wke", with the length of 3.
Note that the answer must be a substring, "pwke" is a subsequence and not a substring.
Solution 1
class Solution {
public:
int lengthOfLongestSubstring(string s) {
int ans = 0;
int temp = 0;
int cur = 0;
unordered_map<char,int> Record;
for (int i = 0; i < s.length(); i++) {
if (Record.find(s[i]) != Record.end()&&Record[s[i]] > cur) {
temp = i - Record[s[i]];
cur = Record[s[i]] + 1;
Record[s[i]] = i;
} else {
temp += 1;
ans = temp > ans? temp : ans;
Record[s[i]] = i;
}
}
return ans;
}
};
Solution 2
class Solution {
public:
int lengthOfLongestSubstring(string s) {
int ans = 0;
int cur = 0;
unordered_map<char,int> Record;
for (int i = 0; i < s.length(); i++) {
if (Record.find(s[i]) != Record.end()) {
cur = max(cur, Record[s[i]]+1);
}
ans = max(ans, i-cur+1);
Record[s[i]] = i;
}
return ans;
}
};
Summary
- 感觉这道题应该由更好的解法，用vector dict(256,-1)更好。