Compress the String

Time Limit: 5 Seconds
Memory Limit: 65536 KB

Dan is playing a game with Ben. Ben gives Dan a long string `S`, and
Dan needs to compress `S` to a list or short strings:
`s[1]`, `s[2]`, ..., `s[N]`. `S` only
contains lowercase letters. Each `s[i]` can contain lowercase
letters and digits, but only digits between `i`+1 and `N`,
inclusive, are allowed for `s[i]`. For example, when `N` = 4,
allowed digits for `s[2]` will be '3' and '4'.

In order to decompress such a list of strings into a single string, we'll
apply string decompress algorithm for each string one by one, in reverse order
(from `s[N]` to `s[1]`). The decompressing algorithm for a
string is easy: just replace each digit in the string by the corresponding
decompressed string with that digit as index. That is to say, for digit
`i` in the string, it will be replaced by the decompressed string
`s[i]`. Because we are applying decompressing algorithm in reverse
order, `s[i]` will always be decompressed before it is used to
replace a digit in other strings. When all the strings are decompressed, the
decompressed string of `s[1]` will be the final result. If the
decompressing result is `S`, we say `S` can be compressed
to this list of strings.

Now Ben decides the number of short strings Dan can use (`N`), as well
as the length limit for each short string. Dan needs to decide whether it is
possible to compress `S` to `N` short strings under this
limit.

#### Input

There are multiple test cases (no more than 150). For each case, there will be
three lines. The first line gives an integer `N`
(1 ≤ `N` ≤ 4), which is the number of short strings Dan can use.
The second line gives `N` integers `L[1]`, ...
`L[N]` (1 ≤ `L[i]` ≤ 4), which means the length of
string `s[i]` should be at most `L[i]`. The third line gives
the string `S`. The length of `S` will be between 1 and 500,
inclusive. `S` will only contain lowercase letters.

#### Output

For each case, if it is possible to compress `S` into `N`
strings and the length of each string is no more than the limit, output "Yes".
Otherwise, output "No".

#### Sample Input

1
1
aa
4
4 4 4 4
ttttttttttttttt

#### Sample Output

No
Yes

Author:

**HANG, Hang**
Contest:

**The 2011 ACM-ICPC Asia Dalian Regional Contest**
Submit
Status