New codeforces dynamic programing problem added ps name -> F1. Korney Korneevich and XOR (easy version)

Dynamic Programming/(CODEFORCES) F1. Korney Korneevich and XOR (easy version).cpp

@@ -0,0 +1,71 @@
+
+#include <iostream>
+#include <bits/stdc++.h>
+using namespace std;
+#define ll long long int
+
+template<typename T>
+T maxt(T a,T b){return (a>b)?a:b;}
+template<typename T>
+T mint(T a,T b){return (a<b)?a:b;}
+
+int main() {
+
+ll test_case_number=1;
+
+for(ll test=0;test<test_case_number;test++){
+
+    ll n;
+    cin>>n;
+    vector<ll>arr(n+1);// take input 1 - indexed
+    for(ll i=1;i<=n;i++)cin>>arr[i];
+
+    vector<vector<ll>>dp(n+1,vector<ll>(513,-1));  // dp[i][x] represent the
+    // minimum value of the last picked element in the subsequence formed from first i
+    // elements of array such that the xor of all of them equals to x.
+
+
+    for(ll i=1;i<=n;i++){ 
+        for(ll x=0;x<=512;x++){
+
+            if(arr[i]>=dp[i-1][x] && dp[i-1][x]!=-1){  // if we can take the element
+
+                if(dp[i][x^arr[i]]==-1)dp[i][x^arr[i]]=arr[i];  //checks if the value is -1, if so we just add the new number else
+                else dp[i][x^arr[i]]=mint<ll>(dp[i][x^arr[i]],arr[i]); // we take the minimum of the two values
+
+            }
+
+
+            if(dp[i-1][x]!=-1){ // if we cannot take the element
+
+                if(dp[i][x]==-1)dp[i][x]=dp[i-1][x]; // value remains same if it is -1 else
+                else dp[i][x]=mint<ll>(dp[i-1][x],dp[i][x]); // take the minimum of the two values
+
+            }
+
+
+            if(dp[i][arr[i]]==-1)dp[i][arr[i]]=arr[i]; // if we are starting a new subsequence from i th position.
+            else dp[i][arr[i]]=mint<ll>(dp[i][arr[i]],arr[i]); // take the minimum of the two values
+
+        }
+    }
+    set<ll>ans;
+    ans.insert(0); // base case
+
+    for(ll i=1;i<=n;i++){
+        for(ll x=0;x<=512;x++){
+            if(dp[i][x]!=-1){
+                ans.insert(x);  // take all possible values.
+            }
+        }
+    }
+    // output
+    cout<<ans.size()<<endl;
+    for(auto nei:ans){
+        cout<<nei<<" ";
+    }
+    cout<<endl;
+
+}
+return 0;
+}