\n Recently, many companies are conducting coding tests during the hiring process. In this article, I will cover a problem that can help you prepare for coding tests using the Swift programming language, and I will explain in detail how to solve that problem efficiently.\n <\/p>\n
\n Given an integer array \n \n This problem is quite famous and can be solved in various ways. The most basic approach is to use a double loop, which has a time complexity of O(n^2). However, let’s explore a more efficient way.\n <\/p>\n \n You can use a method of iterating through the given array and storing each element in a hash map. By using a hash map, you can reduce the search time to O(1), thereby decreasing the overall time complexity to O(n).\n <\/p>\n \n When you run the above code, it will print the result \n This algorithm demonstrates an optimized approach to the given problem. Using the hash map allows us to solve the problem with an average time complexity of O(n). However, in the worst case, performance can degrade due to hash collisions, so it’s essential to use an appropriate hash function.\n <\/p>\n \n In this article, we explored how to solve coding test problems using Swift. The hash map approach can be applied in various situations and can significantly help in writing efficient code. I encourage you to continue solving various algorithm problems to improve your skills.\n <\/p>\n \n There will be more courses covering various algorithm problems and their solutions, so please stay tuned!\n <\/p>\n <\/body><\/p>\n","protected":false},"excerpt":{"rendered":"nums<\/code> and an integer target<\/code>, you need to solve the problem of finding the two indices in the array such that their sum is equal to target<\/code>. It is assumed that each input has exactly one solution, and you may not use the same element twice.\n <\/p>\nInput Format<\/h3>\n
\n
nums<\/code>: [2, 7, 11, 15]<\/li>\ntarget<\/code>: 9<\/li>\n<\/ul>\nOutput Format<\/h3>\n
[0, 1]<\/code> (nums[0] + nums[1] = 2 + 7 = 9)\n <\/p>\nProblem Analysis<\/h2>\n
Efficient Approach: Using Hash Map<\/h2>\n
Steps to Solve the Problem<\/h2>\n
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current<\/code> and target - current<\/code>.<\/li>\ntarget - current<\/code> exists in the hash map, return the corresponding index and the current index.<\/li>\nSwift Code<\/h3>\n
\nlet nums = [2, 7, 11, 15]\nlet target = 9\n\nfunc twoSum(nums: [Int], target: Int) -> [Int]? {\n var numDict = [Int: Int]()\n \n for (index, num) in nums.enumerated() {\n let complement = target - num\n \n if let complementIndex = numDict[complement] {\n \/\/ Return the two indices\n return [complementIndex, index]\n }\n \n \/\/ Add the current number and index to the hash map\n numDict[num] = index\n }\n \n \/\/ Return nil if no solution exists\n return nil\n}\n\nif let result = twoSum(nums: nums, target: target) {\n print(result) \/\/ [0, 1]\n}\n <\/pre>\nResult Verification<\/h2>\n
[0, 1]<\/code>. This confirms that the sum of nums[0]<\/code> and nums[1]<\/code> is equal to target<\/code>.\n <\/p>\nOptimization Considerations<\/h2>\n
Conclusion<\/h2>\n