Given a string s consisting only of characters a, b and c.
Return the number of substrings containing at least one occurrence of all these characters a, b and c.
Example 1:
Input: s = "abcabc" Output: 10 Explanation: The substrings containing at least one occurrence of the characters a, b and c are "abc", "abca", "abcab", "abcabc", "bca", "bcab", "bcabc", "cab", "cabc" and "abc" (again).
Example 2:
Input: s = "aaacb" Output: 3 Explanation: The substrings containing at least one occurrence of the characters a, b and c are "aaacb", "aacb" and "acb".
Example 3:
Input: s = "abc" Output: 1
Constraints:
3 <= s.length <= 5 x 10^4s only consists of a, b or c characters.struct Solution;
impl Solution {
fn number_of_substrings(s: String) -> i32 {
let mut count: [usize; 3] = [0; 3];
let s: Vec<u8> = s.bytes().collect();
let n = s.len();
let mut j = 0;
let mut res = 0;
for i in 0..n {
count[(s[i] - b'a') as usize] += 1;
while count[0] > 0 && count[1] > 0 && count[2] > 0 {
count[(s[j] - b'a') as usize] -= 1;
j += 1;
}
res += j;
}
res as i32
}
}
#[test]
fn test() {
let s = "abcabc".to_string();
let res = 10;
assert_eq!(Solution::number_of_substrings(s), res);
let s = "aaacb".to_string();
let res = 3;
assert_eq!(Solution::number_of_substrings(s), res);
let s = "abc".to_string();
let res = 1;
assert_eq!(Solution::number_of_substrings(s), res);
}