aparler/RosettaCodeData
1
0
Fork 0
Code Issues 12 Pull requests 3 Projects Releases Packages Wiki Activity Actions

Data commit

Browse source
This commit is contained in:
Ingy döt Net 2023-07-01 11:58:00 -04:00
parent 7387c8f97b
commit cb5bb5e222
199093 changed files with 3378972 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

74
Task/Minimal-steps-down-to-1/C-sharp/minimal-steps-down-to-1.cs Normal file
View file

@ -0,0 +1,74 @@
using System;
using System.Collections.Generic;
using System.Linq;
public static class MinimalSteps
{
public static void Main() {
var (divisors, subtractors) = (new int[] { 2, 3 }, new [] { 1 });
var lookup = CreateLookup(2_000, divisors, subtractors);
Console.WriteLine($"Divisors: [{divisors.Delimit()}], Subtractors: [{subtractors.Delimit()}]");
PrintRange(lookup, 10);
PrintMaxMins(lookup);
lookup = CreateLookup(20_000, divisors, subtractors);
PrintMaxMins(lookup);
Console.WriteLine();
subtractors = new [] { 2 };
lookup = CreateLookup(2_000, divisors, subtractors);
Console.WriteLine($"Divisors: [{divisors.Delimit()}], Subtractors: [{subtractors.Delimit()}]");
PrintRange(lookup, 10);
PrintMaxMins(lookup);
lookup = CreateLookup(20_000, divisors, subtractors);
PrintMaxMins(lookup);
}
private static void PrintRange((char op, int param, int steps)[] lookup, int limit) {
for (int goal = 1; goal <= limit; goal++) {
var x = lookup[goal];
if (x.param == 0) {
Console.WriteLine($"{goal} cannot be reached with these numbers.");
continue;
}
Console.Write($"{goal} takes {x.steps} {(x.steps == 1 ? "step" : "steps")}: ");
for (int n = goal; n > 1; ) {
Console.Write($"{n},{x.op}{x.param}=> ");
n = x.op == '/' ? n / x.param : n - x.param;
x = lookup[n];
}
Console.WriteLine("1");
}
}
private static void PrintMaxMins((char op, int param, int steps)[] lookup) {
var maxSteps = lookup.Max(x => x.steps);
var items = lookup.Select((x, i) => (i, x)).Where(t => t.x.steps == maxSteps).ToList();
Console.WriteLine(items.Count == 1
? $"There is one number below {lookup.Length-1} that requires {maxSteps} steps: {items[0].i}"
: $"There are {items.Count} numbers below {lookup.Length-1} that require {maxSteps} steps: {items.Select(t => t.i).Delimit()}"
);
}
private static (char op, int param, int steps)[] CreateLookup(int goal, int[] divisors, int[] subtractors)
{
var lookup = new (char op, int param, int steps)[goal+1];
lookup[1] = ('/', 1, 0);
for (int n = 1; n < lookup.Length; n++) {
var ln = lookup[n];
if (ln.param == 0) continue;
for (int d = 0; d < divisors.Length; d++) {
int target = n * divisors[d];
if (target > goal) break;
if (lookup[target].steps == 0 || lookup[target].steps > ln.steps) lookup[target] = ('/', divisors[d], ln.steps + 1);
}
for (int s = 0; s < subtractors.Length; s++) {
int target = n + subtractors[s];
if (target > goal) break;
if (lookup[target].steps == 0 || lookup[target].steps > ln.steps) lookup[target] = ('-', subtractors[s], ln.steps + 1);
}
}
return lookup;
}
private static string Delimit<T>(this IEnumerable<T> source) => string.Join(", ", source);
}