NOIP 2005 等价表达式 题解

题意

给一个表达式然后再给n个表达式，判断是否等价

一道大模拟题，将a带为数，并且取模防止溢出

#include<bits/stdc++.h>
using namespace std;
const int mod=10007;
char w[55],c[55];
int a[100],t1,t2,x,n;
long long ans[5],c1[55],c2[55],c3[55];
int power(int x,int y){
	int tmp=1;
	while(y){
		if(y&1) tmp=(tmp*x)%mod;
		x=(x*x)%mod;
		y>>=1;
	}
	return tmp%mod;
}
void clu(){
	int m1=c1[t2],n1=c1[t2-1],m2=c2[t2],n2=c2[t2-1],m3=c3[t2],n3=c3[--t2]; 
	switch(w[t1--]){
        case '+':c1[t2]=(n1+m1+mod)%mod; c2[t2]=(n2+m2+mod)%mod; c3[t2]=(n3+m3+mod)%mod; break;
        case '-':c1[t2]=(n1-m1+mod)%mod; c2[t2]=(n2-m2+mod)%mod; c3[t2]=(n3-m3+mod)%mod; break;
        case '*':c1[t2]=(n1*m1+mod)%mod; c2[t2]=(n2*m2+mod)%mod; c3[t2]=(n3*m3+mod)%mod; break;
        case '^':c1[t2]=power(n1,m1); c2[t2]=power(n2,m2); c3[t2]=power(n3,m3); break;
    }
}
void js(){
    x=0;
    for(int i=0;i<strlen(c);i++){
        if(c[i]=='a') {c1[++t2]=3;c2[t2]=7;c3[t2]=13;} 
        else if(isdigit(c[i])) x=x*10+c[i]-'0';
        else{
            if(x!=0){c1[++t2]=x;c2[t2]=x;c3[t2]=x;x=0;}
            if(a[c[i]]==0)continue;
            if(c[i]=='('||t1==0&&c[i]!=')') w[++t1]=c[i]; 
            else{ 
                if(a[c[i]]<a[w[t1]]){
                	if(c[i]!=')') w[++t1]=c[i]; 
					else{ 
                        while(w[t1]!='('&&t1) clu();   
                        if(w[t1]=='(')t1--;
                    }
                }  
                else{
                    while(a[c[i]]>=a[w[t1]]&&t1) clu(); 
                    if(c[i]!=')') w[++t1]=c[i];
                }
            } 
        }
    }
    if(x!=0){c1[++t2]=x;c2[t2]=x;c3[t2]=x;x=0;}
    while (t1)clu();
}
int main(){
	a['(']=5;a[')']=1;a['^']=2;a['*']=a['/']=3;a['+']=a['-']=4;
	gets(c);
	scanf("%d",&n);
	js();
	gets(c);
	ans[1]=c1[1];ans[2]=c2[1];ans[3]=c3[1];
	for(int i=1;i<=n;++i){
        t1=t2=0;gets(c);js(); 
        if(ans[1]==c1[1]%mod&&ans[2]==c2[1]%mod&&ans[3]==c3[1]%mod) 
        printf("%c",i+64);
	}
	return 0;
}