nyoj305

题意：表达式求值
思路：栈的运用。
AC代码：

#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <string>
#include <stack>
#include <queue>
using namespace std;
const int maxn=500;
char ch[maxn];

void calc(char *ch){
    stack<int>s;   //数字
    stack<char>ss;  // 运算符号
    stack<char>sss; //比较符号
    int len=strlen(ch);
    for(int i=0; i<len; i++){
        if(ch[i]==',') continue;
        if(ch[i]=='m') continue;
        if(ch[i]=='a' && ch[i+1]=='d') {
            sss.push(ch[i+1]); i+=2;
        }else if(ch[i]=='i'){
            sss.push(ch[i]); i+=1;
        }else if(ch[i]=='a' && ch[i+1]=='x'){
            sss.push(ch[i]); i+=1;
        }
        else if(ch[i]=='('){
            ss.push(ch[i]);
        }
        else if(ch[i]==')'){
            int xx=s.top();
            s.pop();
            int yy=s.top();
            s.pop();
            if(sss.top()=='i'){
                s.push(min(xx,yy));
            }else if(sss.top()=='d'){
                s.push(xx+yy);
            }else if(sss.top()=='a') {
                s.push(max(xx,yy));
            }
            sss.pop();
            ss.pop();
        }
        else if(ch[i]>='0' && ch[i]<='9'){
            int xx=0;
            while(ch[i]>='0' && ch[i]<='9'){
                xx=xx*10+ch[i]-'0'; i++;
            }
            i=i-1;
            s.push(xx);
        }
    }
    printf("%d\n",s.top());
}


int main(){
    int t;
    scanf("%d",&t);
    while(t--){
        scanf("%s",ch);
        calc(ch);
    }

    return 0;
}