added DP Knapsack Problem

DP/EditDistance.cpp

@@ -0,0 +1,44 @@
+#include<iostream>
+#include<cstring>
+using namespace std;
+
+int editDistance(string s1, string s2){
+    int m=s1.length();
+    int n=s2.length();
+
+    int **dp=new int*[m+1];
+    for(int i=0;i<=m;i++)
+    {
+        dp[i]=new int[n+1];
+    }
+    for(int i=0;i<=m;i++)
+    {
+        dp[i][0]=i;
+    }
+    for(int i=0;i<=n;i++)
+    {
+        dp[0][i]=i;
+    }
+    for(int i=1;i<=m;i++)
+    {
+        for(int j=1;j<=n;j++)
+        {
+            if(s1[m-i]==s2[n-j])
+                dp[i][j]=dp[i-1][j-1];
+            else
+            {
+                dp[i][j]=1+min(dp[i][j-1],min(dp[i-1][j-1],dp[i-1][j]));
+            }
+        }
+    }
+    return dp[m][n];
+}
+
+int main(){
+	string s1, s2;
+	cout<<"Enter first string - ";
+	cin>>s1;
+	cout<<"Enter second string - ";
+	cin>>s2;
+	cout<<"Edit Distance is - "<<editDistance(s1, s2)<<endl;
+}

DP/knapsack0-1.cpp

@@ -0,0 +1,46 @@
+#include<iostream>
+#include <cstring>
+#include <climits>
+using namespace std;
+long int size[1000];
+long int price[1000];
+long long dp[1001][1001];
+int knapsack(int n,int c){
+	//base case
+	if(n==0 || c==0){
+		return 0;
+	}
+	//look up
+	if(dp[n][c]!=-1){
+		return dp[n][c];
+	}
+	//rec case
+	int op1,op2;
+	op1=op2=INT_MIN;
+    if(c>=size[n-1]){
+        op1=price[n-1]+knapsack(n-1,c-size[n-1]); //including the nth item
+    }
+	op2=knapsack(n-1,c); //excluding the nth item
+	dp[n][c]=max(op1,op2);
+    return dp[n][c];
+}
+
+int main() {
+	int n,s;
+	cin>>n>>s;
+	for(int i=0;i<n;i++){
+		cin>>size[i];
+	}
+	for(int i=0;i<n;i++){
+		cin>>price[i];
+	}
+    memset(dp,-1,sizeof dp);
+	for(int i=0;i<=n;i++){
+		dp[i][0]=0;
+	}
+	for(int j=0;j<=s;j++){
+		dp[0][j]=0;
+	}
+	cout<<knapsack(n,s)<<endl;
+	return 0;
+}