【对拍】生成合法的中缀代数表达式

#include<bits/stdc++.h>
using namespace std;
const int maxn=1000005;
#define int long long
#define rep(i,j,k) for(int i=(j);i<=(k);++i)
#define dow(i,j,k) for(int i=(j);i>=(k);--i)
#define pr pair
#define pb push_back
#define mkp make_pair
#define fi first
#define se second
int t,n,m,k;
inline int max(int a,int b) {
	return a>b?a:b;
}
inline int min(int a,int b) {
	return a>b?b:a;
}
inline int read() {
	int x=0;
	char ch=getchar();
	while(1) {
		if (ch>='A'&&ch<='F') {
			x=ch-'A'+10;
			return x;
		} else if(ch>='0'&&ch<='9') {
			x=ch-48;
			return x;
		}
		ch=getchar();
	}
}
int gp(int x,int y) {
//	if(y==x)
//	return x;
	int t;
	while((t=rand())<=0)
		srand(time(0));
	return t%(y-x+1)+x;
}
int gp() {
	int t;
	while((t=rand())<=0)
		srand(time(0));
	return t;
}
char ope[]= {'+','-','*','/','^'};
signed main() {
	ios::sync_with_stdio(false),cin.tie(NULL);
	freopen("data.in","w",stdout);
	srand(time(0));
	t=gp(1,20);
	cout<<t<<endl;
	while(t--) {
		n=gp(1,7);
		int cont=0;
		rep(i,1,n) {
			while(cont>=0&&rand()>20000) {
				cont++;
				cout<<"(";
			}
			cout<<(char)('A'+i-1);
			while(cont>0&&rand()>20000) {
				cont--;
				cout<<")";
			}
			if(i!=n)
				cout<<ope[gp()%5];
		}
		while(cont>0) {
			cont--;
			cout<<")";
		}
		cout<<'#'<<endl;
	}


	return 0;
}