adding some problems from cses and codeforces

Codeforces/codeforces_problemset/110A.cpp

@@ -0,0 +1,27 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+typedef unsigned long long ull;
+
+int checkLuckyNumber(string n) {
+
+    ull count = 0;
+
+    for(ull i = 0; n[i] != '\0'; ++i) {
+        if(n[i] == '7' || n[i] == '4')
+            count++;
+    }
+
+    if(count == 7 || count == 4)
+        return 1;
+    else
+        return 0;
+
+}
+
+int main(){
+
+    string num; cin >> num;
+    cout << (checkLuckyNumber(num) ? "YES" : "NO");
+
+}

Codeforces/codeforces_problemset/1619A.cpp

@@ -0,0 +1,27 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+int checkSquareStr(string str) {
+
+    string str1 = "", str2 = "";
+    int size = str.length();
+    for(int i = 0; i < size; ++i) {
+        if(i < size/2)
+            str1.push_back(str[i]);
+        else
+            str2.push_back(str[i]);
+    }
+
+    return str1 == str2;
+
+}
+
+int main() {
+
+    int n; cin >> n;
+    while(n--) {
+        string str; cin >> str;
+        cout << (checkSquareStr(str) ? "Yes" : "No") << endl;
+    }
+
+}

Codeforces/codeforces_problemset/797A.cpp

@@ -0,0 +1,53 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+int main()
+{
+
+    int n, k;
+    cin >> n >> k;
+    vector<int> fact;
+
+    if(k == 1) {
+        cout << n << endl;
+        return 0;
+    }
+
+    int count = 0;
+    for (int i = 2; i * i <= n; ++i)
+    {
+        if (n % i == 0 and count < k)
+        {
+            while (n % i == 0 and count < k)
+            {
+                n /= i;
+                fact.push_back(i);
+                count++;
+
+                if (count == k - 1 and n != 1)
+                {
+                    fact.push_back(n);
+                    n /= n;
+                    count++;
+                }
+            }
+        }
+    }
+
+    if (n != 1)
+    {
+        fact.push_back(n);
+        count++;
+    }
+
+    if (count == k)
+    {
+        for (auto x : fact)
+            cout << x << " ";
+        cout << endl;
+    }
+    else
+    {
+        cout << -1 << endl;
+    }
+}