Cod sursa(job #2357421)

Utilizator niculaestefan22Stefan Niculae niculaestefan22 Data 27 februarie 2019 13:09:38
Problema Evaluarea unei expresii Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.5 kb
#include <iostream>
#include <fstream>
#include <cstring>
#include <stack>
#include <vector>

using namespace std;

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

char s[100005];
int n,Next[100005];
stack < int > st;

inline int e(const int st,const int dr)
{
    vector < int > v;
    int nr,x,semn,sol,i;
    x=0;
    sol=0;
    semn=1;
    for(i=st;i<=dr;i++)
    {
        if(s[i]=='(')
        {
            x=e(i+1,Next[i]-1);
            i=Next[i];
            continue;
        }
        if('0'<=s[i]&&s[i]<='9')
        {
            x=x*10+(s[i]-'0');
            continue;
        }
        if(semn==0)
            v.back()=v.back()*x;
        else if(semn==-2)
            v.back()=v.back()/x;
        else v.push_back(semn*x);

        if(s[i]=='*')
            semn=0;
        else if(s[i]=='/')
            semn=-2;
        else
        {
            semn=1;
            if(s[i]=='-')
                semn=-1;
        }
        x=0;
    }
    if(semn==0)
        v.back()=v.back()*x;
    else if(semn==-2)
        v.back()=v.back()/x;
    else v.push_back(x*semn);

    for(i=0;i<v.size();i++)
        sol=sol+v[i];

    return sol;


}

void check()
{
    int i;
    for(i=1;i<=n;i++)
    {
        if(s[i]=='(') st.push(i);
        else if(s[i]==')')
        {
            Next[st.top()]=i;
            st.pop();
        }
    }
}

int main()
{
    fin>>s+1;
    n=strlen(s+1);
    check();
    fout<<(e(1,n));
}