UVA - 11988:Broken Keyboard (a.k.a. Beiju Text)

Broken Keyboard (a.k.a. Beiju Text)
出典:UVAタグ:参考資料:『アルゴリズムコンテスト入門経典』P 143類似テーマ:
タイトル
You’re typing a long text with a broken keyboard. Well it’s not so badly broken. The only problem with the keyboard is that sometimes the “home” key or the “end” key gets automatically pressed (internally). You’re not aware of this issue, since you’re focusing on the text and did not even turn on the monitor! After you finished typing, you can see a text on the screen (if you turn on the monitor). In Chinese, we can call it Beiju. Your task is to find the Beiju text.
入力
There are several test cases. Each test case is a single line containing at least one and at most 100,000 letters, underscores and two special characters ‘[’ and ‘]’. ‘[’ means the “Home” key is pressed internally, and ‘]’ means the “End” key is pressed internally. The input is terminated by end-of-file (EOF).
しゅつりょく
For each case, print the Beiju text on the screen.
入力サンプル
This_is_a_[Beiju]_text [[]][][]Happy_Birthday_to_Tsinghua_University
サンプル出力
BeijuThis_is_a__text Happy_Birthday_to_Tsinghua_University
リファレンスコード

#include
#include
const int maxn=100000+5;
int last,cur,next[maxn];
char s[maxn];
int main()
{
	while(scanf("%s",s+1)==1)
	{
		int n=strlen(s+1);
		last=cur=0;
		next[0]=0;
		
		for(int i=1;i<=n;i++)
		{
			char ch=s[i];
			if(ch=='[')cur=0;
			else if(ch==']')cur=last;
			else {
				next[i]=next[cur];
				next[cur]=i;
				if(cur==last) last=i;
				cur=i;
			}
		}
		for(int i=next[0];i!=0;i=next[i])
			printf("%c",s[i]);
		printf("
");
	}
	return 0;
}