Merge pull request neetcode-gh#1873 from AkifhanIlgaz/0169

Create: 0169-majority-element.rs

rust/0169-majority-element.rs

@@ -0,0 +1,48 @@
+use std::collections::HashMap;
+
+impl Solution {
+ // Time Complexity: O(n)
+ // Space Complexity: O(1)
+ // Boyer - Moore Algorithm
+ pub fn majority_element(nums: Vec<i32>) -> i32 {
+ let (mut res, mut count) = (0, 0);
+
+ for n in nums {
+ if count == 0 {
+ res = n;
+ }
+ count += if n == res { 1 } else { -1 };
+ }
+ res
+ }
+
+ // Time Complexity: O(n)
+ // Space Complexity: O(n)
+ // Hashmap
+ pub fn majority_element_2(nums: Vec<i32>) -> i32 {
+ let mut count = HashMap::new();
+
+ let (mut res, mut max_count) = (0, 0);
+
+ for num in nums {
+ *count.entry(num).or_insert(0) += 1;
+ res = if *count.get(&num).unwrap() > max_count {
+ num
+ } else {
+ res
+ };
+ max_count = i32::max(*count.get(&num).unwrap(), max_count);
+ }
+ res
+ }
+
+ // Time Complexity: O(nlogn)
+ // Space Complexity: O(1)
+ // Sorting
+ pub fn majority_element_3(nums: Vec<i32>) -> i32 {
+ // Since we are assured that there will be a majority element which occurs more than nums.len() / 2 times, majority element will be at nums.len() / 2 index
+ let mut nums = nums;
+ nums.sort();
+ nums[nums.len() / 2]
+ }
+}