C. Vanya and Label
time limit per test 1 second
memory limit per test 256 megabytes
input standard input
output standard output
While walking down the street Vanya saw a label "Hide&Seek". Because he is a programmer, he used & as a bitwise AND for these two words represented as a integers in base 64 and got new word. Now Vanya thinks of some string s and wants to know the number of pairs of words of length |s| (length of s), such that their bitwise AND is
equal to s. As this number can be large, output it modulo 109 + 7.
To represent the string as a number in numeral system with base 64 Vanya uses the following rules:
- digits from '0' to '9' correspond to integers from 0 to 9;
- letters from 'A' to 'Z' correspond to integers from 10 to 35;
- letters from 'a' to 'z' correspond to integers from 36 to 61;
- letter '-' correspond to integer 62;
- letter '_' correspond to integer 63.
Input
The only line of the input contains a single word s (1 ≤ |s| ≤ 100 000), consisting of digits, lowercase and uppercase English letters, characters '-' and '_'.
Output
Print a single integer — the number of possible pairs of words, such that their bitwise AND is equal to string s modulo 109 + 7.
Examples
input
z
output
3
input
V_V
output
9
input
Codeforces
output
130653412
Note
For a detailed definition of bitwise AND we recommend to take a look in the corresponding article in Wikipedia.
In the first sample, there are 3
- z&_ = 61&63 = 61 =z
- _&z= 63&61 = 61 =z
- z&z= 61&61 = 61 =z
题解:
有一个字符串,这个字符串的每个字符分别代表着0-63之间的数字,然后问有多少对相同长度的字符串 & (按位与)运算之后,恰好等于这个字符串,又因为
每个字符是独立的,如果每个字符的方案数都知道,然后再全部乘起来就好了。。。。
AC代码:
#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
LL a[1010]={0};
LL mod=1e9+7;
string s;
LL ans;
int main()
{
cin>>s;
//打表
for(int i=0;i<=63;i++)
{
for(int j=0;j<=63;j++)
{
a[i&j]++;
}
}
ans=1;
for(int i=0;i<s.size();i++)
{
int p;
if(s[i]>='0'&&s[i]<='9') p=s[i]-'0';
if(s[i]>='A'&&s[i]<='Z') p=s[i]-'A'+10;
if(s[i]>='a'&&s[i]<='z') p=s[i]-'a'+36;
if(s[i]=='-') p=62;
if(s[i]=='_') p=63;
ans=ans*a[p];
ans%=mod;
}
cout<<ans;
return 0;
}