Cod sursa(job #2815926)

Utilizator edi25Eduard Cioropariu edi25 Data 10 decembrie 2021 16:59:25
Problema Evaluarea unei expresii Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.56 kb
#include <iostream>
#include <fstream>
#include <cstring>

using namespace std;

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

char s[100005];

int verifparanteze(int st, int dr)
{
    int p=0;
    for(int i=st;i<=dr;i++)
    {
        if(s[i]==')')
            p--;
        else if(s[i]=='(')
                p++;
        if(p<0)
            return 0;
    }
    return p==0;
}

int formarenumar(int st, int dr)
{
    int nr=0;
    for(int i=st;i<=dr;i++)
    {
        int c=s[i]-'0';
        nr=nr*10+c;
    }
    return nr;
}

int semn(int st,int dr, char semn1,char semn2)
{
    int p=0; //paranteze
    for(int i=dr;i>=st;i--)
    {
        if(s[i]==')')
            p--;
        else if(s[i]=='(')
                p++;
        else
            if((s[i]==semn1 || s[i]==semn2)&&p==0)
                return i;
    }
    return -1;
}

int eval(int st, int dr)
{
    if(s[st]=='(' && s[dr]==')')
    if(verifparanteze(st+1,dr-1))
    {
        return eval(st+1,dr-1);
    }
    int p=semn(st,dr,'+','-'); //pozitie semn
    if(p==-1)
    {
        p=semn(st,dr,'*','/');
    }
    if(p==-1)
        return formarenumar(st,dr);
    switch(s[p])
    {
        case '+':
            return eval(st,p-1)+eval(p+1,dr);
        case '-':
            return eval(st,p-1)-eval(p+1,dr);
        case '/':
            return eval(st,p-1)/eval(p+1,dr);
        case '*':
            return eval(st,p-1)*eval(p+1,dr);
    }
}

int main()
{
    fin>>s;
    fout<<eval(0,strlen(s)-1);

    return 0;
}