LeetCode-in-Java
3121. Count the Number of Special Characters II
Medium
You are given a string word. A letter c is called special if it appears both in lowercase and uppercase in word, and every lowercase occurrence of c appears before the first uppercase occurrence of c.
Return the number of special letters in word.
Example 1:
Input: word = “aaAbcBC”
Output: 3
Explanation:
The special characters are 'a', 'b', and 'c'.
Example 2:
Input: word = “abc”
Output: 0
Explanation:
There are no special characters in word.
Example 3:
Input: word = “AbBCab”
Output: 0
Explanation:
There are no special characters in word.
Constraints:
1 <= word.length <= 2 * 105wordconsists of only lowercase and uppercase English letters.
Solution
import java.util.Arrays;
public class Solution {
public int numberOfSpecialChars(String word) {
int[] small = new int[26];
Arrays.fill(small, -1);
int[] capital = new int[26];
Arrays.fill(capital, Integer.MAX_VALUE);
int result = 0;
for (int i = 0; i < word.length(); i++) {
char a = word.charAt(i);
if (a < 91) {
capital[a - 65] = Math.min(capital[a - 65], i);
} else {
small[a - 97] = i;
}
}
for (int i = 0; i < 26; i++) {
if (-1 != small[i] && Integer.MAX_VALUE != capital[i] && capital[i] > small[i]) {
result++;
}
}
return result;
}
}