cf 223B.Two Strings

 1 #include<bits/stdc++.h>
 2 #define LL long long 
 3 #define  N 100005
 4 using namespace std;
 5 inline int ra()
 6 {
 7     int x=0,f=1; char ch=getchar();
 8     while (ch<‘0‘ || ch>‘9‘) {if (ch==‘-‘) f=-1; ch=getchar();}
 9     while (ch>=‘0‘ && ch<=‘9‘) {x=x*10+ch-‘0‘; ch=getchar();}
10     return x*f;
11 }
12 char s[N<<1],t[N<<1];
13 int L[N<<1],R[N<<1],last[N<<1];
14 int main()
15 {
16     scanf("%s%s",s,t);
17     memset(last,-1,sizeof(last));
18     int j=0,slen=strlen(s),tlen=strlen(t);
19     for (int i=0; i<slen; i++)
20     {
21         L[i]=last[s[i]-‘a‘];
22         if (j<tlen && s[i]==t[j])
23         {
24             L[i]=j;
25             j++;
26         }
27         last[s[i]-‘a‘]=L[i];
28     }
29     memset(last,-1,sizeof(last));
30     j=tlen-1;
31     for (int i=slen-1; i>=0; i--)
32     {
33         R[i]=last[s[i]-‘a‘];
34         if (j>=0 && s[i]==t[j])
35         {
36             R[i]=j;
37             j--;
38         }
39         last[s[i]-‘a‘]=R[i];
40     }
41     bool ok=1;
42     for (int i=0; i<slen; i++)
43         if (L[i]==-1 || R[i]==-1 || L[i]<R[i])
44         {
45             ok=0;
46             break;
47         }
48     ok?puts("Yes"):puts("No");
49     return 0;
50 }