|
| 1 | +/** |
| 2 | + * [229] Majority Element II |
| 3 | + * |
| 4 | + * Given an integer array of size n, find all elements that appear more than ⌊ n/3 ⌋ times. |
| 5 | + * |
| 6 | + * Note: The algorithm should run in linear time and in O(1) space. |
| 7 | + * |
| 8 | + * Example 1: |
| 9 | + * |
| 10 | + * |
| 11 | + * Input: [3,2,3] |
| 12 | + * Output: [3] |
| 13 | + * |
| 14 | + * Example 2: |
| 15 | + * |
| 16 | + * |
| 17 | + * Input: [1,1,1,3,3,2,2,2] |
| 18 | + * Output: [1,2] |
| 19 | + * |
| 20 | + */ |
| 21 | +pub struct Solution {} |
| 22 | + |
| 23 | +// submission codes start here |
| 24 | + |
| 25 | +impl Solution { |
| 26 | + pub fn majority_element(nums: Vec<i32>) -> Vec<i32> { |
| 27 | + if nums.is_empty() { return vec![] } |
| 28 | + let (mut vote0, mut vote1, mut candidate0, mut candidate1) = (0, 0, -1, -2); |
| 29 | + for &num in nums.iter() { |
| 30 | + if num == candidate0 { |
| 31 | + vote0 += 1; |
| 32 | + } else if num == candidate1 { |
| 33 | + vote1 += 1; |
| 34 | + } else if vote0 == 0 { |
| 35 | + candidate0 = num; |
| 36 | + vote0 = 1; |
| 37 | + } else if vote1 == 0 { |
| 38 | + candidate1 = num; |
| 39 | + vote1 = 1; |
| 40 | + } else { |
| 41 | + vote0 -= 1; |
| 42 | + vote1 -= 1; |
| 43 | + } |
| 44 | + } |
| 45 | + // the presents of majority element is not guaranteed, we have to do a double check |
| 46 | + let mut res = Vec::new(); |
| 47 | + for &v in vec![candidate0, candidate1].iter() { |
| 48 | + let mut count = 0; |
| 49 | + for &num in nums.iter() { |
| 50 | + if v == num { |
| 51 | + count += 1; |
| 52 | + } |
| 53 | + } |
| 54 | + if count > (nums.len() / 3) as i32 { |
| 55 | + res.push(v); |
| 56 | + } |
| 57 | + } |
| 58 | + res |
| 59 | + } |
| 60 | +} |
| 61 | + |
| 62 | +// submission codes end |
| 63 | + |
| 64 | +#[cfg(test)] |
| 65 | +mod tests { |
| 66 | + use super::*; |
| 67 | + |
| 68 | + #[test] |
| 69 | + fn test_229() { |
| 70 | + assert_eq!(Solution::majority_element(vec![1,1,1,2,2,2,3,3,3]), vec![]); |
| 71 | + assert_eq!(Solution::majority_element(vec![1,1,1,2,2,3,3,3]), vec![1,3]); |
| 72 | + assert_eq!(Solution::majority_element(vec![1]), vec![1]); |
| 73 | + assert_eq!(Solution::majority_element(vec![5,6,6]), vec![6]); |
| 74 | + assert_eq!(Solution::majority_element(vec![1,2,3,4]), vec![]); |
| 75 | + } |
| 76 | +} |
0 commit comments