Smallest window in a string containing all the characters of another string

Author: spaceman-dev

Some_More_Strings/README.md

@@ -28,4 +28,11 @@
  Output:
   It sa longdy ear.
   Geks fore
- Explanation:For the 1st test case. Print first "I" and then ignore next "i". Similarly print first space then ignore next space. and so on.
+ Explanation:For the 1st test case. Print first "I" and then ignore next "i". Similarly print first space then ignore next space. and so on.
+
+## 4. Smallest window in a string containing all the characters of another string:
+ Given two strings S and P. Find the smallest window in the string S consisting of all the characters(including duplicates) of the string P. Return "-1" in case there is no such window present. In case there are multiple such windows of same length, return the one with the least starting index. 
+ Example 1:
+ Input: S = "timetopractice", P = "toc"
+ Output: toprac
+ Explanation: "toprac" is the smallest substring in which "toc" can be found.

Some_More_Strings/SmallestWindowInAStringContainingAllTheCharactersOfAnotherString.cpp

@@ -0,0 +1,63 @@
+// { Driver Code Starts
+#include<bits/stdc++.h>
+using namespace std;
+
+
+ // } Driver Code Ends
+class Solution
+{
+ public:
+ //Function to find the smallest window in the string s consisting
+ //of all the characters of string p.
+ string smallestWindow (string s, string p)
+ {
+ // Your code here
+ int map[256] = {0};
+ int count = 0;
+ for(int i = 0 ; i < p.length() ; i++)
+ {
+ if(map[p[i]] == 0)
+ count++;
+ map[p[i]]++;
+ }
+ int res = INT_MAX, ind = 0, i = 0, j = 0;
+ while(j < s.length())
+ {
+ map[s[j]]--;
+ if(map[s[j]] == 0)
+ count--;
+ while(count == 0)
+ {
+ if(res > j - i + 1)
+ {
+ res = min(res, j - i + 1);
+ ind = i;
+ }
+ map[s[i]]++;
+ if(map[s[i]] > 0)
+ count++;
+ i++;
+ }
+ j++;
+ }
+ return res == INT_MAX ? "-1" : s.substr(ind, res);
+ }
+};
+
+// { Driver Code Starts.
+int main()
+ {
+ int t;
+ cin>>t;
+ while(t--)
+ {
+ string s;
+ cin>>s;
+ string pat;
+ cin>>pat;
+ Solution obj;
+ cout<<obj.smallestWindow(s, pat)<<endl;
+ 
+ }
+return 0;
+} // } Driver Code Ends