README_EN.md

1100. Find K-Length Substrings With No Repeated Characters

中文文档

Description

Given a string s and an integer k, return the number of substrings in s of length k with no repeated characters.

 

Example 1:

Input: s = "havefunonleetcode", k = 5
Output: 6
Explanation: There are 6 substrings they are: 'havef','avefu','vefun','efuno','etcod','tcode'.

Example 2:

Input: s = "home", k = 5
Output: 0
Explanation: Notice k can be larger than the length of s. In this case, it is not possible to find any substring.

 

Constraints:

• 1 <= s.length <= 104
• s consists of lowercase English letters.
• 1 <= k <= 104

Solutions

Python3

class Solution:
    def numKLenSubstrNoRepeats(self, s: str, k: int) -> int:
        ans = j = 0
        mp = {}
        for i, c in enumerate(s):
            if c in mp:
                j = max(j, mp[c] + 1)
            mp[c] = i
            if i - j + 1 >= k:
                ans += 1
        return ans

Java

class Solution {
    public int numKLenSubstrNoRepeats(String s, int k) {
        int ans = 0;
        Map<Character, Integer> mp = new HashMap<>();
        for (int i = 0, j = 0; i < s.length(); ++i) {
            char c = s.charAt(i);
            if (mp.containsKey(c)) {
                j = Math.max(j, mp.get(c) + 1);
            }
            mp.put(c, i);
            if (i - j + 1 >= k) {
                ++ans;
            }
        }
        return ans;
    }
}

C++

class Solution {
public:
    int numKLenSubstrNoRepeats(string s, int k) {
        int ans = 0;
        unordered_map<int, int> mp;
        for (int i = 0, j = 0; i < s.size(); ++i) {
            char c = s[i];
            if (mp.count(c)) j = max(j, mp[c] + 1);
            mp[c] = i;
            if (i - j + 1 >= k) ++ans;
        }
        return ans;
    }
};

Go

func numKLenSubstrNoRepeats(s string, k int) int {
	mp := make(map[rune]int)
	ans, j := 0, 0
	for i, c := range s {
		if v, ok := mp[c]; ok {
			j = max(j, v+1)
		}
		mp[c] = i
		if i-j+1 >= k {
			ans++
		}
	}
	return ans
}

func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}

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