0076-minimum-window-substring.cpp

classSolution {
public:
 string minWindow(string s, string t) {
 unordered_map<char, int> mp,check;
for (auto i : t) {
 mp[i]++;
 }
for (auto i : s) {
 check[i]++;
 }
for (auto i : mp) {
if (i.second > check[i.first])
return"";
 }
int len = mp.size(), i = 0, j = 0, cnt = len;
 string ans = s;
while (j<s.length()) {
if (mp.count(s[j])) {
 mp[s[j]]--;
if (!mp[s[j]])
 cnt--;
 }
if (!cnt) {
while (!cnt) {
 string temp = s.substr(i, j - i + 1);
 ans = temp.length() < ans.length() ? temp : ans;
if (mp.count(s[i]))
 mp[s[i]]++;
if (mp.count(s[i]) and mp[s[i]] > 0)
 {
 cnt++;
 i++;
break;
 }
 i++;
 }
 }
 j++;
 }
return ans;
 }
};