Codeforces Round 138 (Div. 1)
B
Two Strings
Codeforces
1900
原题
← AC →
翻译中…

A subsequence of length $|*x*|$ of string $*s* = *s*_{1}*s*_{2}... *s*_{|*s*|}$ (where $|*s*|$ is the length of string $*s*$) is a string $*x* = *s*_{*k*_{1}}*s*_{*k*_{2}}... *s*_{*k*_{|*x*|}}$ $(1 ≤ *k*_{1} < *k*_{2} < ... < *k*_{|*x*|} ≤ |*s*|)$.

翻译中…

You've got two strings — $*s*$ and $*t*$. Let's consider all subsequences of string $*s*$, coinciding with string $*t*$. Is it true that each character of string $*s*$ occurs in at least one of these subsequences? In other words, is it true that for all $*i*$ $(1 ≤ *i* ≤ |*s*|)$, there is such subsequence $*x* = *s*_{*k*_{1}}*s*_{*k*_{2}}... *s*_{*k*_{|*x*|}}$ of string $*s*$, that $*x* = *t*$ and for some $*j*$ $(1 ≤ *j* ≤ |*x*|)$ $*k*_{*j*} = *i*$.

翻译中…

Input

翻译中…

The first line contains string $*s*$, the second line contains string $*t*$. Each line consists only of lowercase English letters. The given strings are non-empty, the length of each string does not exceed $2·10^{5}$.

翻译中…

Output

翻译中…

Print "Yes" (without the quotes), if each character of the string $*s*$ occurs in at least one of the described subsequences, or "No" (without the quotes) otherwise.

翻译中…

Note

翻译中…

In the first sample string $*t*$ can occur in the string $*s*$ as a subsequence in three ways: abab, abab and abab. In these occurrences each character of string $*s*$ occurs at least once.

翻译中…

In the second sample the 4-th character of the string $*s*$ doesn't occur in any occurrence of string $*t*$.

翻译中…

In the third sample there is no occurrence of string $*t*$ in string $*s*$.

翻译中…

样例

Input #1
abab
ab
Output #1
Yes
InputCopy OutputCopy
Input #2
abacaba
aba
Output #2
No
InputCopy OutputCopy
Input #3
abc
ba
Output #3
No
InputCopy OutputCopy
题目信息
题号
223B
时间限制
2 s
内存限制
256 MB
标签
数据结构
动态规划
字符串

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