# Concise C++ Brute force based on previous problems

• ``````class Solution {
public:
bool validWordAbbreviation(string word, string abbr) {
int i = 0, j = 0;
while (i < word.size() && j < abbr.size()) {
if (isdigit(abbr[j])) {
if (abbr[j] == '0') return false;
int val = 0;
while (j < abbr.size() && isdigit(abbr[j]))
val = val * 10 + abbr[j++] - '0';
i += val;
}
else if (word[i++] != abbr[j++]) return false;
}
return i == word.size() && j == abbr.size();
}

void backtrack2(string& word, int begin, string str, vector<pair<int, string>>& res, int counts, int times) {
if (begin == word.size()) {
res.push_back({times + max(counts - 1, 0), str + (counts > 0 ? to_string(counts) : "")});
return;
}
backtrack2(word, begin + 1, str, res, counts + 1, times);
backtrack2(word, begin + 1, str + (counts > 0 ? to_string(counts) : "") +
word[begin], res, 0, times + max(counts - 1, 0));
}

vector<pair<int, string>> generateAbbreviations(string& word) {
vector<pair<int, string>> res;
backtrack2(word, 0, "", res, 0, 0);
return res;
}

string minAbbreviation(string target, vector<string>& dictionary) {
vector<pair<int, string>> abbrs = generateAbbreviations(target);
auto comp = [](const pair<int, string>& p1, const pair<int, string>& p2){ return p1.first > p2.first; };
sort(abbrs.begin(), abbrs.end(), comp);
for (auto& abbr : abbrs) {
int i = 0;
for (; i < dictionary.size(); i++)
if (validWordAbbreviation(dictionary[i], abbr.second)) break;
if (i == dictionary.size()) return abbr.second;
}
return "";
}
};
``````

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