chore(CPlusPlus): add sliding windows (#853)

algorithms/CPlusPlus/README.md

@@ -33,6 +33,7 @@
 - [Sparse Matrix](Arrays/sparse_matrix.cpp)
 
 
+
 ## Dynamic-Programming
 
 - [Longest Common Subsequence](Dynamic-Programming/longest-common-subsequence.cpp)
@@ -128,6 +129,7 @@
 - [Boyer Moore pattern search](Strings/Boyer_Moore.cpp)
 - [Longest common prefix](Strings/longest-common-prefix.cpp)
 - [First unique character in the string](Strings/first-unique-character.cpp)
+- [Sliding Window to match target string](Strings/sliding-window.cpp)
 
 ## Trees
 

algorithms/CPlusPlus/Strings/sliding-window.cpp

@@ -0,0 +1,42 @@
+/*
+Description: A program to find target sub string in given string 
+
+Approach: Using sliding window technique to compare every possible substring with the target string.
+It also supports variable length target inputs since we are initialising window size with size of target
+
+Time complexity: O(n)
+*/
+
+#include <iostream>
+#include <string>
+
+using namespace std;
+
+void sliding(string s,string target){
+    int window_size=target.size();
+    bool notfound=true;
+    for(int i=0;i<s.size();i++){
+        
+        string value = s.substr(i,window_size);
+       
+        if(target==value){
+            cout<<target<<" found at "<<i<<" and "<<i+window_size<<endl;
+            notfound = false;
+        }
+    }
+    if(notfound)
+        cout<<"Target Not found";
+}
+
+int main() {
+    string target="Ipsum";
+    string s = "Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsu";
+    sliding(s,target);
+    
+    cout<<"\nenter the target string:";
+    cin>>target;
+
+    sliding(s,target);
+    
+    return 0;
+}