hdu 3350 #define is unsafe（栈的应用）

http://acm.hdu.edu.cn/showproblem.php?pid=3350

Problem Description

Have you used #define in C/C++ code like the code below?
#include <stdio.h> #define MAX(a , b) ((a) > (b) ? (a) : (b)) int main() {   printf("%d\n" , MAX(2 + 3 , 4));   return 0; }
Run the code and get an output: 5, right? You may think it is equal to this code:
#include <stdio.h> int max(a , b) {  return ((a) > (b) ? (a) : (b));  } int main() {   printf("%d\n" , max(2 + 3 , 4));   return 0; }
But they aren't.Though they do produce the same anwser , they work in two different ways. The first code, just replace the MAX(2 + 3 , 4) with ((2 + 3) > (4) ? (2 + 3) : 4), which calculates (2 + 3) twice. While the second calculates (2 + 3) first, and send the value (5 , 4) to function max(a , b) , which calculates (2 + 3) only once.
What about MAX( MAX(1+2,2) , 3 ) ? Remember "replace". First replace: MAX( (1 + 2) > 2 ? (1 + 2) : 2 , 3) Second replace: ( ( ( 1 + 2 ) > 2 ? ( 1 + 2 ) : 2 ) > 3 ? ( ( 1 + 2 ) > 2 ? ( 1 + 2 ) : 2 ) : 3). The code may calculate the same expression many times like ( 1 + 2 ) above. So #define isn't good.In this problem,I'll give you some strings, tell me the result and how many additions(加法) are computed.

 

Input

The first line is an integer T(T<=40) indicating case number. The next T lines each has a string(no longer than 1000), with MAX(a,b), digits, '+' only(Yes, there're no other characters). In MAX(a,b), a and b may be a string with MAX(c,d), digits, '+'.See the sample and things will be clearer.

 

Output

For each case, output two integers in a line separated by a single space.Integers in output won't exceed 1000000.

 

Sample Input

6 MAX(1,0) 1+MAX(1,0) MAX(2+1,3) MAX(4,2+2) MAX(1+1,2)+MAX(2,3) MAX(MAX(1+2,3),MAX(4+5+6,MAX(7+8,9)))+MAX(10,MAX(MAX(11,12),13))

 

Sample Output

1 0 2 1 3 1 4 2 5 2 28 14

 

思路：用栈容器，模拟过程

#include<iostream>
#include<stack>
using namespace std;
struct Nod
{
    int val,cnt;
};

stack<Nod> Ns;
stack<char> sig;

void s_clear()
{
    while(!Ns.empty())
    {
        Ns.pop();
    }
    while(!sig.empty())
    {
        sig.pop();
    }
}

int main()
{
    int t;
    scanf("%d",&t);
    getchar();
    while(t--)
    {
        char str[1010];
        gets(str);
        s_clear();
        Nod temp,temp2;
        temp.cnt=temp.val=0;
        int i;
        for(i=0;str[i];i++)
        {
            if(str[i]=='(')
            {
                sig.push(str[i]);
                temp.cnt=temp.val=0;
            }
            else if(str[i]==',')
            {
                while(!sig.empty()&&sig.top()=='+')
                {
                    temp2=Ns.top();
                    temp.val+=temp2.val;
                    temp.cnt+=temp2.cnt+1;
                    sig.pop();
                    Ns.pop();
                }
                Ns.push(temp);
                temp.cnt=temp.val=0;
            }
            else if(str[i]==')')
            {
                while(!sig.empty()&&sig.top()=='+')
                {
                    temp2=Ns.top();
                    temp.val+=temp2.val;
                    temp.cnt+=temp2.cnt+1;
                    sig.pop();
                    Ns.pop();
                }
                temp2=Ns.top();
                if(temp2.val>temp.val)
                {
                    temp.val=temp2.val;
                    temp.cnt+=2*temp2.cnt;
                }
                else
                {
                    temp.cnt=2*temp.cnt+temp2.cnt;
                }
                sig.pop();
                Ns.pop();
            }
            else if(str[i]=='+')
            {
                sig.push(str[i]);
                Ns.push(temp);
                temp.cnt=temp.val=0;
            }
            else if(str[i]>='0'&&str[i]<='9')
            {
                temp.val=10*temp.val+str[i]-'0';
            }
        }
        while(!sig.empty()&&sig.top()=='+')
        {
            temp2=Ns.top();
            temp.val+=temp2.val;
            temp.cnt+=temp2.cnt+1;
            sig.pop();
            Ns.pop();
        }
        printf("%d %d\n",temp.val,temp.cnt);
    }
    return 0;
}