Cod sursa(job #1889291)

Utilizator Burbon13Burbon13 Burbon13 Data 22 februarie 2017 17:44:41
Problema Evaluarea unei expresii Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.37 kb
#include <cstdio>
#include <cstring>
#include <cstdlib>

using namespace std;

const int nmx = 100002;

char s[nmx];

void reduc_parant(int &st, int &dr)
{
    while(s[st] == '(' && s[dr] == ')')
    {
        int k = 1;
        for(int i = st + 1; i < dr; ++i)
        {
            if(s[i] == '(')
                ++ k;
            else if(s[i] == ')')
                -- k;
            if(not k)
                return;
        }
        ++ st;
        -- dr;
    }
}

int eval(int st, int dr)
{
    reduc_parant(st,dr);

    int k = 0;

    for(int i = dr; i >= st; --i)
    {
        if(s[i] == ')')
            ++ k;
        else if(s[i] == '(')
            -- k;
        if(not k && s[i] == '+')
            return eval(st,i-1) + eval(i+1,dr);
        if(not k && s[i] == '-')
            return eval(st,i-1) - eval(i+1,dr);
    }

    for(int i = dr; i >= st; --i)
    {
        if(s[i] == ')')
            ++ k;
        else if(s[i] == '(')
            -- k;
        if(not k && s[i] == '*')
            return eval(st,i-1) * eval(i+1,dr);
        if(not k && s[i] == '/')
            return eval(st,i-1) / eval(i+1,dr);
    }

    return atoi(s+st);
}

int main()
{
    freopen("evaluare.in", "r", stdin);
    freopen("evaluare.out", "w", stdout);
    scanf("%s", s);
    printf("%d\n", eval(0,strlen(s)-1));
    return 0;
}