[Programare]Valori

[Hertz]

Am o bucata specifica de text care reprezinta o valoare specifica.O calculez astfel :

- incep citirea din stanga spre dreapta

- daca un caracter e cifra , il adaug la suma mea

- daca e un 'x' , il sterg si merg inapoi 2 pozitii

- continui pana ajung la sfarsitul stringului

De exemplu stringul '123x456' are valoarea 26 .

Care e valoarea stringului :

93752xxx746x27x1754xx90x93xxxxx238x44x75xx08750912738x8461x8759383xx328x4x4935903x6x5550360535004x0xx945958961296x267x8842xxx5x6xx61x4x48482x80xxx83316843x7x4x83x9521731xxx25x51xx457x6x5x9698222x771237745034x5133592x27xx8x87xx35221x36x0x50x23x7x63x998418xx

?

[tromfil]

Se mai pot face optimizari. Adica sa facem o inmultire in functie de cati de x gasim, dar n-are rost ca stringul e mic. E bine?

1492

<?php
$s = '93752xxx746x27x1754xx90x93xxxxx238x44x75xx08750912738x8461x8759383xx328x4x4935903x6x5550360535004x0xx945958961296x267x8842xxx5x6xx61x4x48482x80xxx83316843x7x4x83x9521731xxx25x51xx457x6x5x9698222x771237745034x5133592x27xx8x87xx35221x36x0x50x23x7x63x998418xx';
$suma = 0;
for ($i=0;$i<strlen($s);$i++)
{
	if (is_numeric($s{$i}))
		$suma += $s{$i};
	else
	{
		$a = strpos($s,'x');
		$b = $a+1;
		$s = substr($s,0,$a).substr($s,$b,(strlen($s)-$);
		$i=$i-3;
	}
}
echo $suma;
?>

[CyberWolf08]

Raspuns: 1492

Codul in VB.net ca il aveam deschis cand am vazut challenge-ul

 Dim a As String
        a = "93752xxx746x27x1754xx90x93xxxxx238x44x75xx08750912738x8461x8759383xx328x4x4935903x6x5550360535004x0xx945958961296x267x8842xxx5x6xx61x4x48482x80xxx83316843x7x4x83x9521731xxx25x51xx457x6x5x9698222x771237745034x5133592x27xx8x87xx35221x36x0x50x23x7x63x998418xx"

        Dim i, s As Integer
        While i < a.Length()
            If (a.Chars(i) = "x") Then
                a = a.Remove(i, 1)
                i = i - 2
            End If
            s = s + Val(a.Chars(i)) - "0"
            i = i + 1
        End While
        MsgBox(s)

Later edit: Ah, ca il facuse cineva inainte.

[dranaxum]

Se poate face in O(n) renuntand la strpos, substr etc retinand la fiecare pas ultimile 2 cifre iar in momentul cand se intalneste un x ele se readauga la suma.

In felul asta algoritmul e muuult mai rapid.

Asta e codul:

#include<fstream>
#include<ctype.h>

using namespace std;

ifstream fin("sirhertz.in");
ofstream fout("sirhertz.out");

int main()
{
    char c;
    int s=0,a=0,b=0;
    while(!fin.eof())
    {
        fin>>c;
        if(!fin.eof())
            if(isdigit(c))
            {
                s+=c-'0';
                a=b;
                b=c-'0';
            }
            else
                if(c=='x')
                    s+=a+b;
    }
    fout<<s;
    fin.close();
    fout.close();
    return 0;
}

[dranaxum]

Am tratat cazul general, nu m-am limitat la stringul dat.

[Hertz]

Corect toti 3,imi place abordarea draxanum.Felicitari.

[dranaxum]

Poti pune asta la concursuri pe hackpedia. Sunt curios cine va avea o abordare in O(n).

[cmiN]

Am vazut in php, VB.net, c++, am facut si eu in python . Si eu m-am gandit prima data la ideea lui dranaxum, dar am conceput sursa pentru a urma exact pasii dati de Hertz.

Python

#! /usr/bin/env python
# 09.08.2009 <> 09.08.2009 | cmiN
# Challenge [Programare] Valori (Hertz) @ rstcenter.com


def main():
    string = "93752xxx746x27x1754xx90x93xxxxx238x44x75xx08750912738x8461x8759383xx328x4x4935903x6x5550360535004x0xx945958961296x267x8842xxx5x6xx61x4x48482x80xxx83316843x7x4x83x9521731xxx25x51xx457x6x5x9698222x771237745034x5133592x27xx8x87xx35221x36x0x50x23x7x63x998418xx"
    strlist = list(string)
    strsum, x = 0, 0
    while True:
        try:
            item = strlist[x]
        except:
            break
        if item == "x":
            strlist.remove("x")
            x -= 2
        else:
            strsum += int(item)
            x += 1
    input("The string value is %s." % str(strsum))


if __name__ == "__main__":
    main()