题目描述

2062. 统计字符串中的元音子字符串

题解

此题是一道简单的字符串匹配题，1.暴力求解 2.滑动窗口(待补充)

代码参考：

暴力求解

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
class Solution {
        public int countVowelSubstrings(String word) {
            //1.字符串子串问题，暴力枚举
            if (word.length() < 5) {
                return 0;
            }
            int len = word.length();
            int count = 0;
            for (int i = 0; i < len; i++) {
                int num = 0;
                for (int j = i; j < len; j++) {
                    //普通比较
//                    if (!checkVowel(word.charAt(j))) {
//                        break;
//                    }
//                    set.add(word.charAt(j));
//                    if (set.size() == 5) {
//                        count++;
//                    }
                    //位运算优化，参考字符串hash
                    char c = word.charAt(j);
                    if (c == 'a') {
                        num = (num | 1);
                    } else if (c == 'e') {
                        num = num | (1 << 1);
                    } else if (c == 'i') {
                        num = num | (1 << 2);
                    } else if (c == 'o') {
                        num = num | (1 << 3);
                    } else if (c == 'u') {
                        num = num | (1 << 4);
                    } else {
                        break;
                    }
                    if (num == 31) {
                        count++;
                    }
                }
            }
            return count;
        }

        //必须是元音字符
        //此处可转化为位运算，参考字符串hash
        private boolean checkVowel(char c) {
            if (c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u') {
                return true;
            }
            return false;
        }
    }

滑动窗口

待补充