Cod sursa(job #1583741)
Utilizator | 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;
}