Collections — Dictionary frequency map — C# Programming

Problem

Count word frequency with Dictionary<string,int>.

Hints

TryGetValue or ContainsKey

Your practice code

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Solution

using System;
using System.Collections.Generic;

class Program {
    static void Main() {
        string[] words = { "a", "b", "a", "c", "b", "a" };
        var freq = new Dictionary<string, int>();
        foreach (var w in words)
            freq[w] = freq.TryGetValue(w, out var c) ? c + 1 : 1;
        Console.WriteLine(freq["a"]);
    }
}

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Explanation

TryGetValue avoids double lookup—Dictionary interview best practice.