DP problems, printing LCS and SCS

print longest common subsequence.cpp

@@ -0,0 +1,68 @@
+#include<bits/stdc++.h>
+#define ll long long int
+#define deb(x) cout << #x << " = " << x << endl
+#define deb2(x, y) cout << #x << " = " << x << "," << #y << " = " << y << endl
+#define endl '\n'
+using namespace std;
+
+void lcs(string s1,string s2,int n,int m)
+{
+    int dp[n+1][m+1],i,j;
+    for(i=0;i<n+1;i++)
+        for ( j = 0; j < m+1; j++)
+        {
+            if(i==0||j==0)
+                dp[i][j]=0;
+        }
+    for(i=1;i<n+1;i++)
+        for ( j = 1; j < m+1; j++)
+        {
+            if(s1[i-1]==s2[j-1])
+            {
+                dp[i][j]=1+dp[i-1][j-1];
+            }
+            else
+            {
+                dp[i][j]=max(dp[i-1][j],dp[i][j-1]);
+            }
+        }
+        string str="";
+        i=n,j=m;
+        while(i!=0 && j!=0)
+            {
+                if(s1[i-1]==s2[j-1])
+                {
+                    str+=s1[i-1];
+                    i--; j--;
+                }
+                else
+                {
+                    if(dp[i-1][j]<dp[i][j-1])
+                        j--;
+                    else
+                        i--;
+                }
+            }
+            reverse(str.begin(),str.end());
+            cout<<str<<endl;
+}
+
+void entente()
+{
+   //start solving 
+   int x,y;
+   string s1,s2;
+   cin>>x>>y;
+   cin>>s1>>s2;
+   lcs(s1,s2,x,y);
+}
+
+int main()
+{
+    //ios_base::sync_with_stdio(false);cin.tie(NULL);
+    int t; cin>>t; while(t--)
+    {
+        entente();
+    }
+    return 0;
+}

print shortest common supersequence.cpp

@@ -0,0 +1,85 @@
+#include<bits/stdc++.h>
+#define ll long long int
+#define deb(x) cout << #x << " = " << x << endl
+#define deb2(x, y) cout << #x << " = " << x << "," << #y << " = " << y << endl
+#define endl '\n'
+using namespace std;
+
+void lcs(string s1,string s2,int n,int m)
+{
+    int dp[n+1][m+1],i,j;
+    for(i=0;i<n+1;i++)
+        for ( j = 0; j < m+1; j++)
+        {
+            if(i==0||j==0)
+                dp[i][j]=0;
+        }
+    for(i=1;i<n+1;i++)
+        for ( j = 1; j < m+1; j++)
+        {
+            if(s1[i-1]==s2[j-1])
+            {
+                dp[i][j]=1+dp[i-1][j-1];
+            }
+            else
+            {
+                dp[i][j]=max(dp[i-1][j],dp[i][j-1]);
+            }
+        }
+        string str;
+        i=n,j=m;
+        while(i!=0 && j!=0)
+            {
+                if(s1[i-1]==s2[j-1])
+                {
+                    str.push_back(s1[i-1]);
+                    i--; j--;
+                }
+                else
+                {
+                    if(dp[i-1][j]<dp[i][j-1])
+                        {
+                            j--;
+                            str.push_back(s2[j]);
+                        }
+                    else
+                        {
+                            i--;
+                            str.push_back(s1[i]);
+                        }
+                }
+            }
+        while(i>0)
+        {
+            str.push_back(s1[i-1]);
+            i--;
+        }
+        while (j>0)
+        {
+            str.push_back(s2[j-1]);
+            j--;
+        }
+
+            reverse(str.begin(),str.end());
+            cout<<str<<endl;
+}
+
+void entente()
+{
+   //start solving 
+   int x,y;
+   string s1,s2;
+   cin>>x>>y;
+   cin>>s1>>s2;
+   lcs(s1,s2,x,y);
+}
+
+int main()
+{
+    //ios_base::sync_with_stdio(false);cin.tie(NULL);
+    int t; cin>>t; while(t--)
+    {
+        entente();
+    }
+    return 0;
+}