Merge pull request div-bargali#261 from nakuljn/main

added a dp problem, wildcard matching

Author: jai2dev

C++/Algorithms/Dynamic-Programming/Wildcard_matching.cpp

@@ -0,0 +1,55 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+//creating a function for wildcard matching
+bool isMatch(string s, string p) {
+ int n = s.size();
+ int m = p.size();
+ 
+ //declaring a dp table of size n+1 * m+1
+ vector<vector<int>> dp(n+1, vector<int>(m+1, true));
+ 
+ //initialsing mth column as false
+ for(int i = n-1; i >= 0; i--){
+ dp[i][m] = false;
+ }
+ 
+
+ for(int j = m-1; j >= 0; j--){
+ if(p[j] == '*') dp[n][j] = dp[n][j+1] && true;
+ else dp[n][j] = false;
+ }
+ 
+
+ for(int i = n-1; i >= 0; i--){
+ for(int j = m-1; j >= 0; j--){
+ 
+ //if characters are same we move ahead.
+ if(s[i] == p[j]) dp[i][j] = dp[i+1][j+1];
+ 
+ //if we encounter a '?' we just move ahead in both strings.
+ else if(p[j] == '?') dp[i][j] = dp[i+1][j+1];
+ 
+ //if we encounter a '*' in p we use the then match the remaining string of s with p (no change in position in p)
+ //or we just skip that letter in p.
+ else if(p[j] == '*') dp[i][j] = dp[i+1][j] || dp[i][j+1];
+ 
+ else dp[i][j] = false;
+ }
+ }
+ 
+ return dp[0][0];
+ 
+}
+
+//driver code
+int main(){
+string s = "adceb";
+string p = "*a*b";
+if(isMatch(s, p))
+cout<<"Yes the two patterns match"<<endl;
+else
+cout<<"No the two patterns dont match"<<endl;
+}
+
+// the above program will output yes.