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Author: MathProgrammer

2022/Contests/Educational Round 125/Explanations/Bracket Sequence Deletion Explanation.txt.txt

@@ -0,0 +1,60 @@
+If we meet a (
+
+Then () is a regular balanced string 
+
+And (( is a palindrome 
+
+No matter what, (x is always a good string and we will extract it 
+
+-----
+
+If we meet a )
+
+Then, we cannot get a balanced string since it starts with ) 
+
+We can only get a palindrome 
+
+All we need to do is find the next closed bracket ! 
+
+) ((((( ... ( ) 
+
+is a palindrome !
+
+-----
+
+void solve()
+{
+    int length;
+    string S;
+    cin >> length >> S;
+
+    int minimum_moves = 0, remaining = length;
+    for(int i = 0; i  + 1 < length; i++)
+    {
+        if(S[i] == '(')
+        {
+            minimum_moves++;
+            remaining -= 2;
+            i++;
+        }
+        else if(S[i] == ')')
+        {
+            int j = i + 1;
+            while(j < length && S[j] != ')')
+            {
+                j++;
+            }
+
+            if(j == length)
+            {
+                break;
+            }
+
+            minimum_moves++;
+            remaining -= (j - i + 1); //cout << "i = " << i << " j = " << j << "\n";
+            i = j;
+        }
+    }
+
+    cout << minimum_moves << " " << remaining << "\n";
+}

2022/Contests/Educational Round 125/Explanations/Integer Moves Explanation.txt.txt

@@ -0,0 +1,44 @@
+We can always reach (x, y) in at most 2 moves 
+
+If we are at the origin, then we need 0 moves 
+If (x^2 + y^2) is a perfect square, then we need only 1 move 
+Otherwise, we will go from (0, 0) -> (x, 0) -> (y, 0) in 2 moves !
+
+We will always need at most 2 moves !
+
+------
+
+int is_square(int n)
+{
+    for(int i = 1; i*i <= n; i++)
+    {
+        if(i*i == n)
+        {
+            return true;
+        }
+    }
+
+    return false;
+}
+
+void solve()
+{
+    int x, y;
+    cin >> x >> y;
+
+    int answer = 0;
+    if(x == 0 && y == 0)
+    {
+        answer = 0;
+    }
+    else if(is_square(x*x + y*y))
+    {
+        answer = 1;
+    }
+    else
+    {
+        answer = 2;
+    }
+
+    cout << answer << "\n";
+}

2022/Contests/Educational Round 125/Explanations/XY Sequence Explanation.txt.txt

@@ -0,0 +1,27 @@
+Be greedy and Set A[i] = A[i] + X, unless it exceeds the limit 
+
+------
+
+void solve()
+{
+    int no_of_elements, x, y, max_limit;
+    cin >> no_of_elements >> max_limit >> x >> y;
+
+    long long sum = 0;
+    vector <long long> A(no_of_elements + 1);
+    for(int i = 1; i <= no_of_elements; i++)
+    {
+        if(A[i - 1] + x <= max_limit)
+        {
+            A[i] = A[i - 1] + x;
+        }
+        else
+        {
+            A[i] = A[i - 1] - y;
+        }
+
+        sum += A[i];
+    }
+
+    cout << sum << "\n";
+}