38 lines
991 B
Rust
38 lines
991 B
Rust
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fn digit_to_chars(digit: char) -> Vec<char> {
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match digit {
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'2' => vec!['a', 'b', 'c'],
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'3' => vec!['d', 'e', 'f'],
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'4' => vec!['g', 'h', 'i'],
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'5' => vec!['j', 'k', 'l'],
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'6' => vec!['m', 'n', 'o'],
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'7' => vec!['p', 'q', 'r', 's'],
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'8' => vec!['t', 'u', 'v'],
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'9' => vec!['w', 'x', 'y', 'z'],
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_ => panic!(
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"Character out of range: '{}' is not between '2' and '9'.",
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digit
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),
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}
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}
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pub fn combination(digits: &str) -> Vec<String> {
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let mut combinations: Vec<String> = vec![String::new()];
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for d in digits.chars() {
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let mut temp = Vec::new();
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for c in combinations {
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let chars = digit_to_chars(d);
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for ch in chars {
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temp.push(format!("{}{}", c, ch));
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}
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}
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combinations = temp;
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}
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if combinations.len() == 1 {
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vec![] as Vec<String>
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} else {
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combinations
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}
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}
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