演算法LeetCode TwoSun
Given an array of integers, return indices of the two numbers such that they add up to a specific target.
You may assume that each input would have exactly one solution, and you may not use the same element twice.
static void Main(string[] args)
{
int[] numbers = new[] {3, 21, 9, 5};
int targetNumber = 8;
var res = TwoSum(numbers, targetNumber);
Console.WriteLine($"索引值:{string.Join(",", res)}");
Console.WriteLine($"索引對應的值:{numbers[res[0]]} {numbers[res[1]]}");
Console.ReadLine();
int[] TwoSum(int[] nums, int target)
{
var dictionary = new Dictionary<int, int>();
for (int i = 0; i < nums.Length; i++)
{
var num = target - nums[i];
if (dictionary.ContainsKey(num))
{
return new int[] { dictionary[num], i };
}
//加入到dictionary，key為nums
dictionary[nums[i]] = i;
}
throw new ArgumentException("nums無匹配的2個值，滿足target");
}
}
