DE Shaw Medium csharp

Product of Array Except Self

Animated walkthrough

Step through the algorithm visually — use Play or the step buttons (inspired by AlgoMaster / visualgo).

Step 1 / 1

DE Shaw interview context: Product of Array Except Self 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 #238.

Problem

Product of Array Except Self — DE Shaw interview prep · Arrays & Hashing

Classic interview problem #238.

Input (stdin)

Line 1: space-separated integers

Output (stdout)

n integers, space-separated

Your program must read from stdin and write the answer to stdout (no extra debug text).

Examples

Sample
Input
1 2 3 4
Output
24 12 8 6
Hints
  • Input format: Line 1: space-separated integers
  • DSA Interview 150 — Arrays & Hashing
  • Problem #238
  • Frequently asked at DE Shaw
  • Arrays & Hashing

Your solution

TestStatusDetails
Ready — edit the code above and click Run or Submit.

Solution

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()
    {
var nums = Ria();
int n = nums.Length;
var ans = new int[n];
ans[0] = 1;
for (int i = 1; i < n; i++) ans[i] = ans[i - 1] * nums[i - 1];
int suffix = 1;
for (int i = n - 1; i >= 0; i--) { ans[i] *= suffix; suffix *= nums[i]; }
W(string.Join(" ", ans));
    }
}

Try solving on your own first, then reveal the official answer.

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