Solve first-missing-positive.

source/first_missing_positive/mod.rs

@@ -0,0 +1,36 @@
+pub fn first_missing_positive(mut numbers: Vec<i32>) -> i32 {
+  let numbers_length = numbers.len();
+
+  // Mark all numbers below 1 and above the maximum range as i32::MAX.
+  for index in 0..numbers_length {
+    if numbers[index] < 1 || numbers[index] > numbers_length as i32 {
+      numbers[index] = i32::MAX;
+    }
+  }
+
+  for index in 0..numbers_length {
+    // For each index get its number and subtract 1.
+    let index = numbers[index].abs() as usize - 1;
+
+    // If that index then isn't i32::MAX - 1 (ie. negative or above range).
+    if index as i32 != i32::MAX - 1 {
+      // Then mark the number for that index as negative.
+      numbers[index] = -numbers[index].abs();
+    }
+  }
+
+  // Then the first positive number we find, the index of that number will be
+  // the first missing positive. And if there are only negative numbers, then
+  // the next positive number is the total amount of numbers + 1.
+  numbers
+    .into_iter()
+    .enumerate()
+    .find_map(|(index, number)| {
+      if number.is_positive() {
+        Some(index + 1)
+      } else {
+        None
+      }
+    })
+    .unwrap_or_else(|| numbers_length + 1) as i32
+}

source/fizz_buzz/mod.rs

@@ -0,0 +1,16 @@
+pub fn fizz_buzz(number: i32) -> Vec<String> {
+  let mut result = vec![];
+
+  for index in 1..=number {
+    let string = match (index % 3 == 0, index % 5 == 0) {
+      (true, true) => "FizzBuzz".to_string(),
+      (true, false) => "Fizz".to_string(),
+      (false, true) => "Buzz".to_string(),
+      (false, false) => index.to_string(),
+    };
+
+    result.push(string);
+  }
+
+  result
+}

source/keyboard_row/mod.rs

@@ -0,0 +1,29 @@
+pub fn find_words(words: Vec<String>) -> Vec<String> {
+  // Uncomment FromIterator in Leetcode since they're using Rust Edition 2018.
+  // Edition 2021 has this trait in its prelude.
+
+  // use std::iter::FromIterator;
+  use std::collections::HashSet;
+
+  fn hashset_from_str(string: &str) -> HashSet<char> {
+    std::collections::HashSet::<_>::from_iter(string.to_lowercase().chars())
+  }
+
+  let rows = [
+    hashset_from_str("qwertyuiop"),
+    hashset_from_str("asdfghjkl"),
+    hashset_from_str("zxcvbnm"),
+  ];
+
+  let mut result = vec![];
+
+  for word in words {
+    let word_set = hashset_from_str(&word);
+
+    if rows.iter().any(|row| word_set.is_subset(row)) {
+      result.push(word);
+    }
+  }
+
+  result
+}

source/lib.rs

@@ -3,9 +3,12 @@ pub mod contains_duplicate;
 pub mod contains_duplicate_ii;
 pub mod excel_sheet_column_number;
 pub mod excel_sheet_column_title;
+pub mod first_missing_positive;
+pub mod fizz_buzz;
 pub mod implement_strstr;
 pub mod integer_to_roman;
 pub mod isomorphic_strings;
+pub mod keyboard_row;
 pub mod length_of_last_word;
 pub mod longest_common_prefix;
 pub mod missing_number;
@@ -13,8 +16,10 @@ pub mod palindrome_number;
 pub mod plus_one;
 pub mod reverse_integer;
 pub mod roman_to_integer;
+pub mod set_mismatch;
 pub mod two_sum;
 pub mod valid_anagram;
+pub mod valid_number;
 pub mod valid_palindrome;
 pub mod valid_parenthesis;
 pub mod word_pattern;

source/set_mismatch/mod.rs

@@ -0,0 +1,31 @@
+pub fn find_error_nums(numbers: Vec<i32>) -> Vec<i32> {
+  // Uncomment FromIterator in Leetcode since they're using Rust Edition 2018.
+  // Edition 2021 has this trait in its prelude.
+
+  // use std::iter::FromIterator;
+  use std::collections::HashSet;
+
+  let range = 1..=numbers.len() as i32;
+  let mut numbers_set = HashSet::<_>::new();
+
+  let mut duplicate = 0;
+
+  for number in numbers {
+    if numbers_set.insert(number) {
+      continue;
+    }
+
+    duplicate = number;
+  }
+
+  let mut missing = 0;
+
+  for number in range {
+    if !numbers_set.contains(&number) {
+      missing = number;
+      break;
+    }
+  }
+
+  vec![duplicate, missing]
+}

source/valid_number/mod.rs

@@ -0,0 +1,23 @@
+pub fn is_number(string: String) -> bool {
+  let string = string.to_lowercase();
+
+  if string.contains("inf") || string.contains("nan") {
+    return false;
+  }
+
+  let mut parts = string.split("e");
+
+  let valid_significand = match parts.next() {
+    Some(part) => part.parse::<f64>().is_ok(),
+    None => unreachable!(),
+  };
+
+  let valid_exponent = match parts.next() {
+    Some(part) => part.parse::<isize>().is_ok(),
+    None => true,
+  };
+
+  let nothing_remaining = parts.next().is_none();
+
+  valid_significand && valid_exponent && nothing_remaining
+}

tests/first_missing_positive.rs

@@ -0,0 +1,14 @@
+use leetcode::first_missing_positive::first_missing_positive;
+
+use test_case::test_case;
+
+#[test_case(&[1, 2, 0], 3; "example 1")]
+#[test_case(&[3, 4, -1, 1], 2; "example 2")]
+#[test_case(&[7, 8, 9, 11, 12], 1; "example 3")]
+#[test_case(&[1, 3, 2], 4; "maximum")]
+#[test_case(&[1, 3, 3], 2; "duplicate")]
+#[test_case(&[0], 1; "zero")]
+#[test_case(&(0..=500000).into_iter().collect::<Vec<i32>>(), 500001; "massive")]
+fn test_first_missing_positive(input: &[i32], expected: i32) {
+  assert_eq!(first_missing_positive(input.to_vec()), expected);
+}

tests/fizz_buzz.rs

@@ -0,0 +1,15 @@
+use leetcode::fizz_buzz::fizz_buzz;
+
+use test_case::test_case;
+
+const EXAMPLE_3: &[&str] = &[
+  "1", "2", "Fizz", "4", "Buzz", "Fizz", "7", "8", "Fizz", "Buzz", "11",
+  "Fizz", "13", "14", "FizzBuzz",
+];
+
+#[test_case(3, &["1", "2", "Fizz"]; "example 1")]
+#[test_case(5, &["1", "2", "Fizz", "4", "Buzz"]; "example 2")]
+#[test_case(15, EXAMPLE_3; "example 3")]
+fn test_fizz_buzz(input: i32, expected: &[&str]) {
+  assert_eq!(fizz_buzz(input), expected);
+}

tests/keyboard_row.rs

@@ -0,0 +1,13 @@
+use leetcode::keyboard_row::find_words;
+
+use test_case::test_case;
+
+#[test_case(&["Hello", "Alaska", "Dad", "Peace"], &["Alaska", "Dad"]; "example 1")]
+#[test_case(&["omk"], &[]; "example 2")]
+#[test_case(&["adsdf", "sfd"], &["adsdf", "sfd"]; "example 3")]
+fn test_keyboard_row(input: &[&str], expected: &[&str]) {
+  assert_eq!(
+    find_words(input.iter().map(ToString::to_string).collect()),
+    expected
+  );
+}

tests/set_mismatch.rs

@@ -0,0 +1,12 @@
+use leetcode::set_mismatch::find_error_nums;
+
+use test_case::test_case;
+
+#[test_case(&[1, 2, 2, 4], &[2, 3]; "example 1")]
+#[test_case(&[1, 1], &[1, 2]; "example 2")]
+#[test_case(&[2, 2], &[2, 1]; "edge 1")]
+#[test_case(&[3, 2, 3, 4, 6, 5], &[3, 1]; "edge 2")]
+#[test_case(&[3, 2, 2], &[2, 1]; "edge 3")]
+fn test_set_mismatch(input: &[i32], expected: &[i32]) {
+  assert_eq!(find_error_nums(input.to_vec()), expected);
+}

tests/valid_number.rs

@@ -0,0 +1,13 @@
+use leetcode::valid_number::is_number;
+
+use test_case::test_case;
+
+#[test_case("0", true; "example 1")]
+#[test_case("e", false; "example 2")]
+#[test_case(".", false; "example 3")]
+#[test_case("-inf", false; "infinity")]
+#[test_case("NaN", false; "not a number")]
+#[test_case("", false; "empty")]
+fn test_valid_number(input: &str, expected: bool) {
+  assert_eq!(is_number(input.to_string()), expected);
+}