Following up on the next_permutation from a couple of weeks ago word finder uses next_permutation to find words in character sequences. Uses the aspell C api to look up each permutation. Searching for 3,4,5 and 6 character words in a 6 character sequence takes about 200ms.
Using C++11 meant that I could use a nice lambda expression to process each permutation by passing the function object to the permute() function.
#pragma once
#include "word_accumulator.h"
#include "spell_checker.hpp"
void permute(vector<char> chars, std::function<void (const string&)> f) {
do {
string perm;
for (auto x : chars)
perm += x;
f(perm);
} while (next_permutation(chars.begin(), chars.end()));
}
class word_finder {
const char *seed;
public:
word_finder(const char *seed) : seed(seed) {
}
template<typename T> vector<T> sorted_vector_of(const T *seed) {
vector<T> y(seed, seed + strlen(seed));
sort(y.begin(), y.end());
return y;
}
vector<string> find() {
spell_checker checker;
accumulator<string> accumulator;
permute(sorted_vector_of(seed), [&](const string& w) {
for (int i = 3; i <= w.size(); i++) {
for (int j = 0; j <= w.size() - i; j++) {
string to_check(&w.c_str()[j], i);
accumulator.append_if(to_check, [&](const string& t) {
return checker.is_correct(t);
});
}
}
});
return accumulator.sort_by([](const string& a, const string& b) {
return b.length() == a.length() ? a < b : b.length() > a.length();
});
}
};