leetcode-swift

About

This Xcode project records my solved problem in LeetCode Online Judge.

I hope to be able to provide ideas for everyone to solve the problem on Leetcode OJ through this project.

In this project, I divided the problem into three groups - Easy、Medium、Hard and provide a template.swift to you. If solved a new problem, I will update this project in time!

Use and Example

To run a specific solution, please change the question number in main.swift e.g. q169.getSolution() to run solution for question 169 "Majority Element".

Attention! Because I write code directly inside leetcode judge web, so many getSolution() have no test cases. If you want to test in Xcode, please add test case by yourself!

The structure of each question is as follows:

struct q169 {
    
    class Solution {
        //1.hash table dictionary
        //time complexity:O(n);space complexity:O(n)
        func majorityElement(_ nums: [Int]) -> Int {
            var numCounts = [Int: Int]()
            for num in nums {
                numCounts[num, default: 0] += 1  
            }
            for (key, value) in numCounts {
                if value > nums.count / 2 {
                    return key
                }
            }
            return 0
        }
        //2.moore vote dictionary
        //time complexity:O(n);space complexity:O(1)
        func majorityElement_1(_ nums: [Int]) -> Int {
            var count = 0;var major = nums.first!
            for i in 0..<nums.count {
                if count == 0 {
                    major = nums[i]
                    count = 1
                } else if major == nums[i] {
                    count += 1
                } else {
                    count -= 1
                }
            }
            return major
        }
    }
    
    static func getSolution() -> Void {
        //do test case here!
    }
}

Notes

• If you have good advice or a better solution to a problem, I hope you can communicate with me and we can learn from each other.
• Thank you wty21cn for providing me with template and some problem's ideas.