使用字典(Dictionary)习题

熟悉掌握值查找键并返回所有匹配的键

题目：有一个Dictionary<string, int>，其中键是学生姓名，值是学生成绩。要求编写一个方法，传入一个成绩值，返回所有成绩等于该值的学生姓名的列表。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace 合并两个字典
{
    internal class Program
    {
        static void Main(string[] args)
        {
            Dictionary<string,int>dict1 = new Dictionary<string, int>()
            {
                {"这是1",1 },
                {"这是2",2 }
            };
            Dictionary<string, int> dict2 = new Dictionary<string, int>()
            {
                {"这是3",3 },
                {"这是5",5 }
            };
            Dictionary<string,int>merged= MergedDictinonary(dict1,dict2);
            foreach(KeyValuePair<string,int> pair in merged)
            {
                Console.WriteLine($"键{pair.Key},值{pair.Value}");
            }
        }
        static Dictionary<string, int> MergedDictinonary(Dictionary<string, int> dict1, Dictionary<string, int> dict2)
        {
            Dictionary<string,int>mergeDi = new Dictionary<string,int>(dict1);
            foreach(KeyValuePair<string,int> pair in dict2)
            {
                if (mergeDi.ContainsKey(pair.Key))
                {
                    mergeDi[pair.Key] += pair.Value;
                }
                else
                {
                    mergeDi.Add(pair.Key, pair.Value);
                }
            }
            return mergeDi;
        }
      
    }
}