动态规划 回溯
(s: String)
| 1 | // 动态规划 回溯 |
| 2 | pub fn letter_case_permutation(s: String) -> Vec<String> { |
| 3 | let mut dp: Vec<String> = vec![String::new()]; |
| 4 | let mut current_count = 1; |
| 5 | for c in s.chars().collect::<Vec<char>>() { |
| 6 | if c.is_numeric() { |
| 7 | for i in dp.len()-current_count..dp.len() { |
| 8 | let mut tmp = dp[i].clone(); |
| 9 | tmp.push(c); |
| 10 | dp.push(tmp); |
| 11 | } |
| 12 | } else { |
| 13 | for i in dp.len()-current_count..dp.len() { |
| 14 | let mut tmp_lower = dp[i].clone(); |
| 15 | let mut tmp_upper = dp[i].clone(); |
| 16 | tmp_lower.push(c.to_ascii_lowercase()); |
| 17 | tmp_upper.push(c.to_ascii_uppercase()); |
| 18 | dp.push(tmp_lower); |
| 19 | dp.push(tmp_upper); |
| 20 | } |
| 21 | } |
| 22 | current_count *= 2; |
| 23 | } |
| 24 | dp.retain(|e|e.len() == s.len()); |
| 25 | dp |
| 26 | } |
| 27 | |
| 28 | fn main() { |
| 29 | let s = "a1b2".to_string(); |