added knight tour to backtracking and longest common string to dynamic

Dynamic Programming/longest_common_string.cpp

@@ -0,0 +1,65 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+int max(int a,int b)
+{
+    return (a > b) ? a : b;
+}
+
+int main()
+{
+    char str1[]="DEFBCD";
+    char str2[]="ABDEFJ";
+    int i,j,k;
+    int n=strlen(str1)+1;
+    int m=strlen(str2)+1;
+    //cout<<n<<" "<<m<<"\n";
+    int a[m][n];
+
+    for(i=0;i<m;i++)
+    {
+        for(j=0;j<n;j++)
+        {
+            if(i==0 || j==0)
+                a[i][j]=0;
+
+            else if(str1[i-1] == str2[j-1])
+                    a[i][j]=a[i-1][j-1]+1;
+
+            else
+                a[i][j]=0;
+        }
+    }
+
+
+/*for(i=0;i<m;i++)
+    {
+        for(j=0;j<n;j++)
+            cout<<a[i][j]<<" ";
+        cout<<"\n";
+    }*/
+
+
+int ma=-1;
+int indi,indj;
+for(i=0;i<m;i++)
+    {
+        for(j=0;j<n;j++)
+        {
+            if(a[i][j]>ma)
+            {
+                ma=a[i][j];
+                indi=i;
+                indj=j;
+            }
+        }
+    }
+
+    cout<<str1<<"\n";
+    cout<<str2<<"\n";
+
+    cout<<"longest string size = "<<ma/*<<" "<<indi<<" "<<indj*/<<"\n";
+    for(i=indi-3;i<indi;i++)
+        cout<<str1[i];
+    cout<<"\n";
+}