Which English word has the most permutations which are also English words? (Of course each of the lexible permutations is also an answer. Is "lexible" a sensible term for having the property of being a word?)
Here's some C++ code to look at this:
most_permutable.cpp:
#include <algorithm>
#include <cctype>
#include <fstream>
#include <functional>
#include <iostream>
#include <map>
#include <string>
using namespace std;
template<typename T>
class select2nd {
public:
typedef T argument_type;
typename T::second_type operator()(const T& t) {
return t.second;
}
};
template<typename B, typename U1, typename U2>
class binary_compose {
public:
typedef typename B::result_type result_type;
typedef typename U1::argument_type arg1_type;
typedef typename U2::argument_type arg2_type;
binary_compose(const B& b, const U1& u1, const U2& u2) :
b(b), u1(u1), u2(u2) {}
result_type operator()(const arg1_type& x1,
const arg2_type& x2)
{
return b(u1(x1), u2(x2));
}
private:
B b;
U1 u1;
U2 u2;
};
template<typename B, typename U1, typename U2>
binary_compose<B, U1, U2>
compose2(B b, U1 u1, U2 u2)
{
return binary_compose<B, U1, U2>(b, u1, u2);
}
typedef map<string, int>::iterator iter;
int main(int numArgs, char** args)
{
map<string, int> permutationCounts;
ifstream in("/usr/share/dict/words");
while (in) {
string word;
in >> word;
if (!word.empty() && islower(word[0])) {
sort(word.begin(), word.end());
iter p = permutationCounts.find(word);
if (p != permutationCounts.end()) {
++(*p).second;
}
else {
permutationCounts.insert(make_pair(word, 1));
}
}
}
iter m = max_element(permutationCounts.begin(),
permutationCounts.end(),
compose2(less<int>(),
select2nd<pair<string, int> >(),
select2nd<pair<string, int> >()));
cout << (*m).first << " with " << (*m).second << '\n';
}
Drum roll:
$ g++ -Wall most_permutable.cpp
$ ./a.out
acert with 9
What are the 9?
find_perm.cpp:
#include <algorithm>
#include <cstdio>
#include <fstream>
#include <iostream>
#include <string>
using namespace std;
int main(int numArgs, char** args)
{
if (numArgs != 3) {
cerr << "Usage: find_perm <file> <letters>\n";
return 1;
}
ifstream in(args[1]);
if (!in) {
cerr << "Problem opening " << args[1] << '\n';
perror("");
return 1;
}
string letters(args[2]);
sort(letters.begin(), letters.end());
const string::size_type n = letters.size();
string word;
while (in) {
in >> word;
if (n == word.size()) {
string key(word);
sort(key.begin(), key.end());
if (key == letters) {
cout << word << '\n';
}
}
}
in.close();
}
$ g++ -Wall -o find_perm find_perm.cpp
$ ./find_perm oops
Usage: find_perm <file> <letters>
$ ./find_perm oops oops
Problem opening oops
No such file or directory
$ ./find_perm /usr/share/dict/words trace
caret
carte
cater
crate
creat
creta
react
recta
trace
What the heck is "creat"? Hm. Google doesn't know about it. It is really there though:
$ grep -w -n creat /usr/share/dict/words
45105:creat
