Cod sursa(job #1583741)

Utilizator oldatlantianSerban Cercelescu oldatlantian Data 29 ianuarie 2016 12:06:46
Problema Evaluarea unei expresii Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 4.01 kb
#include <cstdio>
#include <cctype>
#include <cstring>
#include <stack>
using namespace std;
char str[100005];

stack<int> vals;
stack<char> ops;

int main(void){
    freopen("evaluare.in","r",stdin);
    freopen("evaluare.out","w",stdout);
    int t,l,n=0;
    gets(str+1);
    l = strlen(str+1);
    ops.push('(');

    str[0]='(';
    str[l+1]=')';
    str[l+2]='\0';

    for(int i=1; str[i-1]; ++i){
        if(isdigit(str[i])){
            n=n*10+str[i]-'0';
            continue;
        }
        if(isdigit(str[i-1]) && !isdigit(str[i])) vals.push(n), n=0;

        if(str[i]=='('){
            ops.push('(');
            continue;
        }
        if(str[i]==')'){
            while(ops.top()!='('){
                t = vals.top();
                vals.pop();
                switch(ops.top()){
                case '+':
                    vals.top()+=t;
                    break;
                case '-':
                    vals.top()-=t;
                    break;
                case '*':
                    vals.top()*=t;
                    break;
                case '/':
                    vals.top()/=t;
                    break;
                }
                ops.pop();
            }
            ops.pop();
            continue;
        }
        if(str[i]=='+'){
            while(!ops.empty() && ops.top()!='('){
                t = vals.top();
                vals.pop();
                switch(ops.top()){
                case '+':
                    vals.top()+=t;
                    break;
                case '-':
                    vals.top()-=t;
                    break;
                case '*':
                    vals.top()*=t;
                    break;
                case '/':
                    vals.top()/=t;
                    break;
                }
                ops.pop();
            }
            ops.push('+');
            continue;
        }
        if(str[i]=='-'){
            while(!ops.empty() && ops.top()!='('){
                t = vals.top();
                vals.pop();
                switch(ops.top()){
                case '+':
                    vals.top()+=t;
                    break;
                case '-':
                    vals.top()-=t;
                    break;
                case '*':
                    vals.top()*=t;
                    break;
                case '/':
                    vals.top()/=t;
                    break;
                }
                ops.pop();
            }
            ops.push('-');
            continue;
        }
        if(str[i]=='/'){
            if(!ops.empty() && ops.top()!='(' && ops.top()!='+' && ops.top()!='-'){
                t = vals.top();
                vals.pop();
                switch(ops.top()){
                case '+':
                    vals.top()+=t;
                    break;
                case '-':
                    vals.top()-=t;
                    break;
                case '*':
                    vals.top()*=t;
                    break;
                case '/':
                    vals.top()/=t;
                    break;
                }
                ops.pop();
            }
            ops.push('/');
            continue;
        }
        if(str[i]=='*'){
            if(!ops.empty() && ops.top()!='(' && ops.top()!='+' && ops.top()!='-'){
                t = vals.top();
                vals.pop();
                switch(ops.top()){
                case '+':
                    vals.top()+=t;
                    break;
                case '-':
                    vals.top()-=t;
                    break;
                case '*':
                    vals.top()*=t;
                    break;
                case '/':
                    vals.top()/=t;
                    break;
                }
                ops.pop();
            }
            ops.push('*');
            continue;
        }
    }
    printf("%d",vals.top());
    return 0;
}