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Cargo.toml

@@ -31,4 +31,6 @@ members = [
     "find_and_replace_pattern",
     "to_lower_case",
     "evaluate_reverse_polish_notation",
+    "partitioning_into_minimum_number_of_deci_binary_numbers",
+    "maximum_product_of_word_lengths",
 ]

maximum_product_of_word_lengths/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "maximum_product_of_word_lengths"
+version = "0.1.0"
+authors = ["Ryan Li <conbas2019@gmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

maximum_product_of_word_lengths/src/lib.rs

@@ -0,0 +1,96 @@
+pub struct Solution {}
+
+impl Solution {
+    fn share_common_letters(
+        mask_cache: &mut Vec<i32>,
+        i1: usize,
+        w1: &String,
+        i2: usize,
+        w2: &String,
+    ) -> bool {
+        let mask1 = match mask_cache.get(i1) {
+            Some(&x) if x != 0 => x,
+            _ => {
+                let mask = w1
+                    .chars()
+                    .fold(0, |acc, x| acc | 1 << (x as u8 - 'a' as u8));
+                mask_cache[i1] = mask;
+                mask
+            }
+        };
+        let mask2 = match mask_cache.get(i2) {
+            Some(&x) if x != 0 => x,
+            _ => {
+                let mask = w2
+                    .chars()
+                    .fold(0, |acc, x| acc | 1 << (x as u8 - 'a' as u8));
+                mask_cache[i2] = mask;
+                mask
+            }
+        };
+        mask1 & mask2 != 0
+    }
+
+    fn get_length(length_cache: &mut Vec<usize>, index: usize, word: &String) -> usize {
+        match length_cache.get(index) {
+            Some(&l) if l != 0 => l,
+            _ => {
+                let length = word.chars().count();
+                length_cache[index] = length;
+                length
+            }
+        }
+    }
+
+    pub fn max_product(words: Vec<String>) -> i32 {
+        let mut length_cache = vec![0; words.len()];
+        let mut mask_cache = vec![0; words.len()];
+        let mut max = 0;
+        for (i, w1) in words.iter().enumerate() {
+            for j in i + 1..words.len() {
+                let w2 = &words[j];
+                if Self::share_common_letters(&mut mask_cache, i, w1, j, w2) {
+                    continue;
+                }
+                max = max.max(
+                    (Self::get_length(&mut length_cache, i, w1)
+                        * Self::get_length(&mut length_cache, j, w2)) as i32,
+                );
+            }
+        }
+        max
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn it_works(words: Vec<&str>, expected: i32) {
+        assert_eq!(
+            Solution::max_product(words.iter().map(|x| x.to_string()).collect()),
+            expected
+        );
+    }
+
+    #[test]
+    fn example_1() {
+        let words = vec!["abcw", "baz", "foo", "bar", "xtfn", "abcdef"];
+        let expected = 16;
+        it_works(words, expected);
+    }
+
+    #[test]
+    fn example_2() {
+        let words = vec!["a", "ab", "abc", "d", "cd", "bcd", "abcd"];
+        let expected = 4;
+        it_works(words, expected);
+    }
+
+    #[test]
+    fn example_3() {
+        let words = vec!["a", "aa", "aaa", "aaaa"];
+        let expected = 0;
+        it_works(words, expected);
+    }
+}

partitioning_into_minimum_number_of_deci_binary_numbers/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "partitioning_into_minimum_number_of_deci_binary_numbers"
+version = "0.1.0"
+authors = ["Ryan Li <conbas2019@gmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

partitioning_into_minimum_number_of_deci_binary_numbers/src/lib.rs

@@ -0,0 +1,31 @@
+pub struct Solution {}
+
+impl Solution {
+    pub fn min_partitions(n: String) -> i32 {
+        n.chars().max().unwrap() as i32 - '0' as i32
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn it_works(n: &str, expected: i32) {
+        assert_eq!(Solution::min_partitions(n.to_string()), expected);
+    }
+
+    #[test]
+    fn example_1() {
+        it_works("32", 3);
+    }
+
+    #[test]
+    fn example_2() {
+        it_works("82734", 8);
+    }
+
+    #[test]
+    fn example_3() {
+        it_works("27346209830709182346", 9);
+    }
+}