string minWindow(string s, string t) {
if(s.length() < t.length()) return "";
const int ASCII_SIZE = 256;
vector<int> appeared_count(ASCII_SIZE, 0);
vector<int> expected_count(ASCII_SIZE, 0);
for(auto c:t) expected_count[c]++;
int min_width=INT_MAX, min_start=0, win_start=0, appeared=0;
for(size_t win_end=0; win_end<s.length(); win_end++) {
char c = s[win_end];
if(expected_count[c]>0) {
appeared_count[c]++;
if(appeared_count[c] <= expected_count[c]) appeared++;
}
if(appeared == t.length()) {
while(appeared_count[s[win_start]]>expected_count[s[win_start]] || expected_count[s[win_start]]==0) {
appeared_count[s[win_start]]--;
win_start++;
}
if(min_width > (win_end-win_start+1)) {
min_width = win_end-win_start+1;
min_start = win_start;
}
}
}
return min_width == INT_MAX ? "" : s.substr(min_start, min_width);
}
inline std::size_t operator+=(const std::size_t increment)
{
m_count += increment;
on_progress(count(), expected_count());
return m_expected_count;
}
inline bool complete() const
{
return count() >= expected_count();
}
