Longest Substring Without Repeating Characters Program Solution | leetcode Program Solutions

Given a string `s`

, find the length of the **longest substring** without repeating characters.

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**Example 1:**

Input:s = "abcabcbb"Output:3Explanation:The answer is "abc", with the length of 3.

**Example 2:**

Input:s = "bbbbb"Output:1Explanation:The answer is "b", with the length of 1.

**Example 3:**

Input:s = "pwwkew"Output:3Explanation:The answer is "wke", with the length of 3. Notice that the answer must be a substring, "pwke" is a subsequence and not a substring.

**Constraints:**

`0 <= s.length <= 5 * 10`

^{4}`s`

consists of English letters, digits, symbols and spaces.

**Time:**O(n)*O*(*n*)**Space:**O(128) = O(1)*O*(128)=*O*(1)

### Longest Substring Without Repeating Characters Program Solution in C++

```
class Solution {
public:
int lengthOfLongestSubstring(string s) {
int ans = 0;
vector<int> count(128);
for (int l = 0, r = 0; r < s.length(); ++r) {
++count[s[r]];
while (count[s[r]] > 1)
--count[s[l++]];
ans = max(ans, r - l + 1);
}
return ans;
}
};
```

### Longest Substring Without Repeating Characters Program Solution in JAVA

```
class Solution {
public int lengthOfLongestSubstring(String s) {
int ans = 0;
int[] count = new int[128];
for (int l = 0, r = 0; r < s.length(); ++r) {
++count[s.charAt(r)];
while (count[s.charAt(r)] > 1)
--count[s.charAt(l++)];
ans = Math.max(ans, r - l + 1);
}
return ans;
}
}
```

### Longest Substring Without Repeating Characters Program Solution in Python

```
class Solution:
def lengthOfLongestSubstring(self, s: str) -> int:
ans = 0
count = Counter()
l = 0
for r, c in enumerate(s):
count[c] += 1
while count[c] > 1:
count[s[l]] -= 1
l += 1
ans = max(ans, r - l + 1)
return ans
```