carloscn
commented
1 year ago Analysis
fn count_one_bits(num:usize) -> usize
{
let mut count:usize = 0;
let mut input:usize = num;
while input != 0 {
input &= input - 1;
count += 1;
}
return count;
}
pub fn count_good_substrings(s: &str) -> i32
{
if s.len() < 1 {
return 0;
}
let mut ret:i32 = 0;
let mut s_v:Vec<char> = s.chars().collect();
let (mut i, mut j, mut k, mut num, mut n) =
(0usize, 3usize, 0usize, (1 << s.len()) as usize, 0usize);
for n in 0..num {
if count_one_bits(n) != 3 {
continue;
}
j = n;
k = 0;
i = 0;
let mut t_buf:Vec<char> = vec!['0'; 3];
while j != 0 {
if j & 1 == 1 {
t_buf[i] = s_v[k];
i += 1;
}
j >>= 1;
k += 1;
}
t_buf.sort();
t_buf.dedup();
if t_buf.len() == 3 {
println!("the result is {:?}\n", t_buf);
ret += 1;
}
}
return ret;
}
Description
A string is good if there are no repeated characters.
Given a string s, return the number of good substrings of length three in s.
Note that if there are multiple occurrences of the same substring, every occurrence should be counted.
A substring is a contiguous sequence of characters in a string.
Example 1:
Input: s = "xyzzaz" Output: 1 Explanation: There are 4 substrings of size 3: "xyz", "yzz", "zza", and "zaz". The only good substring of length 3 is "xyz".
Example 2:
Input: s = "aababcabc" Output: 4 Explanation: There are 7 substrings of size 3: "aab", "aba", "bab", "abc", "bca", "cab", and "abc". The good substrings are "abc", "bca", "cab", and "abc".
Constraints:
1 <= s.length <= 100 s consists of lowercase English letters.