05 August 2008
最多包含k个不同字符的子字符串的长度 - HashMap记录滑动窗口
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
class Solution {
public int lengthOfLongestSubstringKDistinct(String s, int k) {
Map<Character, Integer> map = new HashMap<>();
int left = 0; // 记录窗口的最左边字符的index
int best = 0;
for(int i = 0; i < s.length(); i++) {
char c = s.charAt(i);
map.put(c, map.getOrDefault(c, 0) + 1);
while (map.size() > k) { // 检查hashmap的size
char leftChar = s.charAt(left);
if (map.containsKey(leftChar)) {
map.put(leftChar, map.get(leftChar) - 1);
if (map.get(leftChar) == 0) {
map.remove(leftChar);
}
}
left++;
}
best = Math.max(best, i - left + 1);
}
return best;
}
}