Coin Change

Medium 30 pts New · no attempts yet csharp

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Coin Change — Myntra interview prep · 1-D Dynamic Programming

Classic interview problem #322.

Input (stdin)

Line 1: coins\nLine 2: amount

Output (stdout)

Min coins or -1

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

Examples

Sample

Input

1 2 5
11

Output

Static hints

Input format: Line 1: coins\nLine 2: amount
DSA Interview 150 — 1-D Dynamic Programming
Problem #322
Frequently asked at Myntra
1-D Dynamic Programming

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Your solution

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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()
    {
        // Read from stdin (see problem statement for format)
        // Line 1: coins\nLine 2: amount

}
}

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Official 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 coins = Ria();
int amount = int.Parse(Console.ReadLine());
int[] dp = new int[amount + 1];
Array.Fill(dp, amount + 1);
dp[0] = 0;
for (int a = 1; a <= amount; a++)
    foreach (var c in coins)
        if (c <= a) dp[a] = Math.Min(dp[a], dp[a - c] + 1);
Wi(dp[amount] > amount ? -1 : dp[amount]);
    }
}

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Explanation

Step 1 / 1

Myntra interview context: Coin Change is a Medium 1-D Dynamic Programming problem — Define state dp[i] and transition from smaller subproblems.

Use the animation above to step through each move before writing code.

Pattern: 1-D Dynamic Programming

Read from stdin, write to stdout. Classic interview problem #322.

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