8-5-2020

Author: safrannn

src/_0017_letter_combinations_of_a_phone_number.rs

@@ -0,0 +1,72 @@
+struct Solution;
+
+use std::collections::HashMap;
+
+impl Solution {
+    pub fn letter_combinations(digits: String) -> Vec<String> {
+        if digits.is_empty() {
+            return vec![];
+        }
+
+        let h_map: HashMap<char, Vec<char>> = [
+            ('2', "abc"),
+            ('3', "def"),
+            ('4', "ghi"),
+            ('5', "jkl"),
+            ('6', "mno"),
+            ('7', "pqrs"),
+            ('8', "tuv"),
+            ('9', "wxyz"),
+            ('0', " "),
+        ]
+        .iter()
+        .map(|(number, letters)| (*number, letters.chars().collect()))
+        .collect();
+
+        let mut current_combination: Vec<char> = vec![];
+        let current_index: usize = 0;
+        let mut result: Vec<String> = vec![];
+        let digits: Vec<char> = digits.chars().collect();
+        Self::dfs(
+            &h_map,
+            &digits,
+            &mut current_combination,
+            current_index,
+            &mut result,
+        );
+        result
+    }
+
+    fn dfs(
+        h_map: &HashMap<char, Vec<char>>,
+        digits: &Vec<char>,
+        current_combination: &mut Vec<char>,
+        current_index: usize,
+        result: &mut Vec<String>,
+    ) {
+        if current_index == digits.len() {
+            result.push(current_combination.iter().collect::<String>());
+        } else {
+            let current_digit: char = digits[current_index];
+            for &c in h_map[&current_digit].iter() {
+                current_combination.push(c);
+                Self::dfs(
+                    h_map,
+                    digits,
+                    current_combination,
+                    current_index + 1,
+                    result,
+                );
+                current_combination.pop();
+            }
+        }
+    }
+}
+
+#[test]
+fn test() {
+    assert_eq!(
+        Solution::letter_combinations("23".to_string()),
+        vec_string!["ad", "ae", "af", "bd", "be", "bf", "cd", "ce", "cf"]
+    )
+}

src/_0038_count_and_say.rs

@@ -0,0 +1,37 @@
+struct Solution;
+
+impl Solution {
+    pub fn count_and_say(n: i32) -> String {
+        if n == 1 {
+            return "1".to_string();
+        }
+
+        let mut previous: Vec<char> = Self::count_and_say(n - 1).chars().collect();
+        previous.push(' ');
+
+        let mut result: String = "".to_string();
+        let mut digit_read: char = previous[0];
+        let mut digit_read_count: u32 = 1;
+
+        for index in 1..previous.len() {
+            if previous[index] == digit_read {
+                digit_read_count += 1;
+            } else {
+                result.push(std::char::from_digit(digit_read_count, 10).unwrap());
+                result.push(digit_read);
+                digit_read = previous[index].clone();
+                digit_read_count = 1;
+            }
+        }
+        result
+    }
+}
+
+#[test]
+fn test() {
+    assert_eq!(Solution::count_and_say(1), "1".to_string());
+    assert_eq!(
+        Solution::count_and_say(30),
+        "3113112221131112311332111213122112311311123112111331121113122112132113121113222112311311221112131221123113112221121113311211131122211211131221131211132221121321132132212321121113121112133221123113112221131112212211131221121321131211132221123113112221131112311332211211133112111311222112111312211311123113322112111312211312111322212321121113121112133221121321132132211331121321132213211231132132211211131221232112111312212221121123222112311311222113111231133211121321321122111312211312111322211213211321322123211211131211121332211231131122211311123113321112131221123113111231121123222112111331121113112221121113122113111231133221121113122113121113221112131221123113111231121123222112111312211312111322212321121113121112131112132112311321322112111312212321121113122122211211232221121321132132211331121321231231121113112221121321132132211322132113213221123113112221133112132123222112111312211312112213211231132132211211131221131211322113321132211221121332211231131122211311123113321112131221123113111231121113311211131221121321131211132221123113112211121312211231131122211211133112111311222112111312211312111322211213211321223112111311222112132113213221133122211311221122111312211312111322212321121113121112131112132112311321322112111312212321121113122122211211232221121321132132211331121321231231121113112221121321132132211322132113213221123113112221133112132123222112111312211312112213211231132132211211131221131211322113321132211221121332211213211321322113311213212312311211131122211213211331121321123123211231131122211211131221131112311332211213211321223112111311222112132113213221123123211231132132211231131122211311123113322112111312211312111322111213122112311311123112112322211213211321322113312211223113112221121113122113111231133221121321132132211331222113321112131122211332113221122112133221123113112221131112311332111213122112311311123112111331121113122112132113121113222112311311221112131221123113112221121113311211131122211211131221131211132221121321132132212321121113121112133221123113112221131112311332111213122112311311123112112322211322311311222113111231133211121312211231131112311211232221121113122113121113222123211211131221132211131221121321131211132221123113112211121312211231131122113221122112133221121321132132211331121321231231121113121113122122311311222113111231133221121113122113121113221112131221123113111231121123222112132113213221133112132123123112111312211322311211133112111312211213211311123113223112111321322123122113222122211211232221121113122113121113222123211211131211121311121321123113213221121113122123211211131221121311121312211213211321322112311311222113311213212322211211131221131211221321123113213221121113122113121113222112131112131221121321131211132221121321132132211331121321232221123113112221131112311322311211131122211213211331121321122112133221121113122113121113222123112221221321132132211231131122211331121321232221121113122113121113222123211211131211121332211213111213122112132113121113222112132113213221232112111312111213322112132113213221133112132123123112111311222112132113311213211221121332211231131122211311123113321112131221123113112221132231131122211211131221131112311332211213211321223112111311222112132113212221132221222112112322211211131221131211132221232112111312111213111213211231131112311311221122132113213221133112132123222112311311222113111231132231121113112221121321133112132112211213322112111312211312111322212321121113121112131112132112311321322112111312212321121113122122211211232221121311121312211213211312111322211213211321322123211211131211121332211213211321322113311213211322132112311321322112111312212321121113122122211211232221121321132132211331121321231231121113112221121321133112132112312321123113112221121113122113111231133221121321132122311211131122211213211321222113222122211211232221123113112221131112311332111213122112311311123112111331121113122112132113121113222112311311221112131221123113112221121113311211131122211211131221131211132221121321132132212321121113121112133221123113112221131112311332111213213211221113122113121113222112132113213221232112111312111213322112132113213221133112132123123112111312211322311211133112111312212221121123222112132113213221133112132123222113223113112221131112311332111213122112311311123112112322211211131221131211132221232112111312111213111213211231132132211211131221131211221321123113213221123113112221131112211322212322211231131122211322111312211312111322211213211321322113311213211331121113122122211211132213211231131122212322211331222113112211".to_string()
+    );
+}

src/lib.rs

@@ -28,6 +28,8 @@ mod _0014_longest_common_prefix;
 //
 mod _0015_3sum;
 //
+mod _0017_letter_combinations_of_a_phone_number;
+//
 mod _0020_valid_parentheses;
 //
 mod _0021_merge_two_sorted_lists;
@@ -38,6 +40,8 @@ mod _0034_find_first_and_last_position_of_element_in_sorted_array;
 //
 mod _0036_valid_sudoku;
 //
+mod _0038_count_and_say;
+//
 mod _0046_permutations;
 //
 mod _0053_maximum_subarray;