add find_maximum_xor (#32)

* init single-number-iii

* update

* init

* init sol for single_number_iii

* foreach

* add more

* init sol2

* add

* clean

* clean

* init missing_number

* add

* add more

* add missing_number

* add mroe

* add sol4

* add sol3

* udpate readme

* init maximum_product_of_word_lengths

* update readme

* minor

* update

* fix readme

* init max_product

* update

* wip

* from &str

* minor

* imnor

* minor

* wip

* minor

* fix

* ???

* fix

* add

* update

* clean

* fix

* init for power_of_four

* update is_power_of_four

* add sol1

* add sol2

* clean

* mark sol

* init get_sum

* fix readme

* add get_sum sol1

* wip

* refactor

* refactor

* add

* add find_the_difference

* add

* draft

* init utf_8_validation

* add valid_utf8

* add utf_8_validation

* cargo fmt

* add sol3

* clean up

* fix

* fix

* init test_read_binary_watch

* add testcases

* minor

* minor

* clean up

* wip

* fix

* fix

* init maximum_xor_of_two_numbers_in_an_array

* add

* add

* fix

* fix

Author: ChrisLinn

README.md

@@ -69,11 +69,11 @@ cargo test
 0389 | [Find the Difference](https://leetcode.com/problems/find-the-difference/) | [C++](https://github.com/kamyu104/LeetCode-Solutions/blob/master/C++/find-the-difference.cpp) [Python](https://github.com/kamyu104/LeetCode-Solutions/blob/master/Python/find-the-difference.py) <br>------br> [Rust](./kamyu104/src/find_the_difference.rs) | _O(n)_ | _O(1)_ | Easy | |
 0393 | [UTF-8 Validation](https://leetcode.com/problems/utf-8-validation/) | [C++](https://github.com/kamyu104/LeetCode-Solutions/blob/master/C++/utf-8-validation.cpp) [Python](https://github.com/kamyu104/LeetCode-Solutions/blob/master/Python/utf-8-validation.py) <br>------br> [Rust](./kamyu104/src/utf_8_validation.rs) | _O(n)_ | _O(1)_ | Medium | |
 0401 | [Binary Watch](https://leetcode.com/problems/binary-watch/) | [C++](https://github.com/kamyu104/LeetCode-Solutions/blob/master/C++/binary-watch.cpp) [Python](https://github.com/kamyu104/LeetCode-Solutions/blob/master/Python/binary-watch.py) <br>------br> [Rust](./kamyu104/src/binary_watch.rs) | _O(1)_ | _O(1)_ | Easy | |
+0411 | [~~Minimum Unique Word Abbreviation~~](https://leetcode.com/problems/minimum-unique-word-abbreviation/) | [C++](https://github.com/kamyu104/LeetCode-Solutions/blob/master/C++/minimum-unique-word-abbreviation.cpp) [Python](https://github.com/kamyu104/LeetCode-Solutions/blob/master/Python/minimum-unique-word-abbreviation.py) | _O(2^n)_ | _O(n)_ | Hard | 🔒 |
+0421 | [Maximum XOR of Two Numbers in an Array](https://leetcode.com/problems/maximum-xor-of-two-numbers-in-an-array/) | [C++](https://github.com/kamyu104/LeetCode-Solutions/blob/master/C++/maximum-xor-of-two-numbers-in-an-array.cpp) [Python](https://github.com/kamyu104/LeetCode-Solutions/blob/master/Python/maximum-xor-of-two-numbers-in-an-array.py) <br>------br> [Rust](./kamyu104/src/maximum_xor_of_two_numbers_in_an_array.rs) | _O(n)_ | _O(n)_ | Medium ||
 
@@ -42,5 +42,14 @@ mod tests {
@@ -42,5 +42,14 @@ mod tests {
                 .map(String::from)
                 .collect::<BTreeSet<String>>()
         );
+        assert_eq!(
+            Solution::read_binary_watch(1)
+                .into_iter()
+                .collect::<BTreeSet<String>>(),
+            vec!["1:00", "2:00", "4:00", "8:00", "0:01", "0:02", "0:04", "0:08", "0:16", "0:32"]
+                .into_iter()
+                .map(Into::into)
+                .collect::<BTreeSet<String>>()
+        );
     }
 }
@@ -2,6 +2,7 @@ mod binary_watch;
 mod bitwise_and_of_numbers_range;
 mod find_the_difference;
 mod maximum_product_of_word_lengths;
+mod maximum_xor_of_two_numbers_in_an_array;
 mod missing_number;
 mod number_of_1_bits;
 mod power_of_four;
@@ -0,0 +1,35 @@
+use std::collections::HashSet;
+
+// Time:  O(n)
+// Space: O(n)
+
+pub struct Solution {}
+impl Solution {
+    pub fn find_maximum_xor(nums: Vec<i32>) -> i32 {
+        let mut result: i32 = 0;
+        for i in (0..32).rev() {
+            result <<= 1;
+            let mut prefixes: HashSet<i32> = HashSet::new();
+            for n in nums.clone() {
+                prefixes.insert(n >> i);
+            }
+            for p in prefixes.clone() {
+                if prefixes.contains(&((result | 1) ^ p)) {
+                    result += 1;
+                    break;
+                }
+            }
+        }
+        result
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_find_maximum_xor() {
+        assert_eq!(Solution::find_maximum_xor(vec![3, 10, 5, 25, 2, 8]), 28);
+    }
+}

kamyu104/src/main.rs

@@ -42,5 +42,14 @@ mod tests {
                 .map(String::from)
                 .collect::<BTreeSet<String>>()
         );
+        assert_eq!(
+            Solution::read_binary_watch(1)
+                .into_iter()
+                .collect::<BTreeSet<String>>(),
+            vec!["1:00", "2:00", "4:00", "8:00", "0:01", "0:02", "0:04", "0:08", "0:16", "0:32"]
+                .into_iter()
+                .map(Into::into)
+                .collect::<BTreeSet<String>>()
+        );
     }
 }

kamyu104/src/maximum_xor_of_two_numbers_in_an_array.rs

@@ -2,6 +2,7 @@ mod binary_watch;
 mod bitwise_and_of_numbers_range;
 mod find_the_difference;
 mod maximum_product_of_word_lengths;
+mod maximum_xor_of_two_numbers_in_an_array;
 mod missing_number;
 mod number_of_1_bits;
 mod power_of_four;

@@ -0,0 +1,35 @@
+use std::collections::HashSet;
+
+// Time:  O(n)
+// Space: O(n)
+
+pub struct Solution {}
+impl Solution {
+    pub fn find_maximum_xor(nums: Vec<i32>) -> i32 {
+        let mut result: i32 = 0;
+        for i in (0..32).rev() {
+            result <<= 1;
+            let mut prefixes: HashSet<i32> = HashSet::new();
+            for n in nums.clone() {
+                prefixes.insert(n >> i);
+            }
+            for p in prefixes.clone() {
+                if prefixes.contains(&((result | 1) ^ p)) {
+                    result += 1;
+                    break;
+                }
+            }
+        }
+        result
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_find_maximum_xor() {
+        assert_eq!(Solution::find_maximum_xor(vec![3, 10, 5, 25, 2, 8]), 28);
+    }
+}