简单TJ

看注释

#include<bits/stdc++.h>
using namespace std;
char ch[114514];//栈
int top;
int main() {
	string s;
	cin >> s;
	for (int i = 0; i < s.size(); i++) {
		if (s[i] != '@')ch[++top] = s[i];//若不是删除符，则入栈
		else if (top > 0)top--;//反之，去栈顶
	}
	for (int i = 1; i <= top; i++) {
		cout << ch[i];//输出
	}
	return 0;
}

当然

	if (s[i] != '@')ch[++top] = s[i];
	else if (top > 0)top--;

}
也可写作____________________________________________________
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