Codeforces Round #401 (Div. 2) D. Cloud of Hashtags

 1 #include<bits/stdc++.h>
 2 #define F(i,a,b) for(int i=a;i<=b;++i)
 3 using namespace std;
 4 typedef long long ll;
 5 
 6 const int N=5e5+7;
 7 char str[N*3];
 8 int st[N],len[N],n,ed;
 9 
10 char find(int i,int j){return str[st[i]+j];}
11 
12 inline void output(int s)
13 {
14     int now=s;
15     while(1)
16     {
17         if(!str[now])return;
18         putchar(str[now++]);
19     }
20 }
21 
22 int main(){
23     scanf("%d",&n);
24     F(i,1,n)
25     {
26         st[i]=ed;
27         scanf("%s",str+ed);
28         len[i]=strlen(str+ed);
29         ed+=len[i]+1;
30     }
31     for(int i=n-1;i>0;i--)
32     {
33         F(j,1,len[i]-1)
34         {
35             int tmp=find(i+1,j)-find(i,j);
36             if(tmp<0)
37             {
38                 str[st[i]+j]=0;
39                 break;
40             }if(tmp>0)break;
41         }
42     }
43     F(i,1,n)output(st[i]),puts("");
44     return 0;
45 }