Submission #2740367

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Source Code Expand

using System;
using System.Collections.Generic;
using System.Linq;

public static class Test
{

    public static IEnumerable<S> Scan<T, S>(this IEnumerable<T> ie, S init, Func<S, T, S> predicate)
    {
        var sum = init;
        foreach(var x in ie)
        {
            yield return sum = predicate(sum, x);
        }
    }
    
    public static IEnumerable<T> StartWith<T>(this IEnumerable<T> ie, T init)
    {
        yield return init;
        foreach(var x in ie)
            yield return x;
    }
    
    public static void Main()
    {
        int.Parse(Console.ReadLine());
        IEnumerable<char> directions = Console.ReadLine();
        
        var cost0 = new {
                cost = directions.Skip(1).Count(x => x == 'E'),
                prev = directions.First()
            };
        
        var costs = directions
            .Skip(1)
            .Scan(
                cost0,
                (s, x) => new {
                    cost = (s.cost + (s.prev == 'W' ? 1 : 0) - (x == 'E' ? 1 : 0)),
                    prev = x
                })
            .StartWith(cost0)
            .Select(x => x.cost);
        
        Console.WriteLine(costs.Min());
    }
}

Submission Info

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