Step through the algorithm visually — use Play or the step buttons (inspired by AlgoMaster / visualgo).
American Express interview context: Group Anagrams is a Medium Arrays & Hashing problem — Use a hash map to trade space for O(1) lookups — classic at onsite rounds.
Use the animation above to step through each move before writing code.
Pattern: Arrays & Hashing
Read from stdin, write to stdout. Classic interview problem #49.
Group Anagrams — American Express interview prep · Arrays & Hashing
Classic interview problem #49.
Input (stdin)
Line 1: n\nNext n lines: strings
Output (stdout)
Number of anagram groups
Your program must read from stdin and write the answer to stdout (no extra debug text).
6 eat tea tan ate nat bat
3
| Test | Status | Details |
|---|
Ready — edit the code above and click Run or Submit.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
class Program
{
static int[] Ria(string line = null)
{
line ??= Console.ReadLine();
if (string.IsNullOrWhiteSpace(line)) return Array.Empty<int>();
return line.Trim().Split(new[] { ' ', ',', '\t' }, StringSplitOptions.RemoveEmptyEntries)
.Select(int.Parse).ToArray();
}
static string[] Rsa()
{
int n = int.Parse(Console.ReadLine());
var arr = new string[n];
for (int i = 0; i < n; i++) arr[i] = Console.ReadLine();
return arr;
}
static void W(params object[] parts) => Console.WriteLine(string.Join(" ", parts));
static void Wb(bool v) => Console.WriteLine(v ? "true" : "false");
static void Wi(int v) => Console.WriteLine(v);
static void Ws(string v) => Console.WriteLine(v);
static void Main()
{
int n = int.Parse(Console.ReadLine());
var strs = new string[n];
for (int i = 0; i < n; i++) strs[i] = Console.ReadLine();
var groups = new Dictionary<string, List<string>>();
foreach (var w in strs) {
var key = new string(w.OrderBy(c => c).ToArray());
if (!groups.ContainsKey(key)) groups[key] = new List<string>();
groups[key].Add(w);
}
Wi(groups.Count);
}
}Try solving on your own first, then reveal the official answer.