Add Project Euler problem 800 solution 1

DIRECTORY.md

@@ -317,6 +317,7 @@
   * [Longest Sub Array](dynamic_programming/longest_sub_array.py)
   * [Matrix Chain Order](dynamic_programming/matrix_chain_order.py)
   * [Max Non Adjacent Sum](dynamic_programming/max_non_adjacent_sum.py)
+  * [Max Product Subarray](dynamic_programming/max_product_subarray.py)
   * [Max Sub Array](dynamic_programming/max_sub_array.py)
   * [Max Sum Contiguous Subsequence](dynamic_programming/max_sum_contiguous_subsequence.py)
   * [Min Distance Up Bottom](dynamic_programming/min_distance_up_bottom.py)
@@ -1016,6 +1017,8 @@
     * [Sol1](project_euler/problem_587/sol1.py)
   * Problem 686
     * [Sol1](project_euler/problem_686/sol1.py)
+  * Problem 800
+    * [Sol1](project_euler/problem_800/sol1.py)
 
 ## Quantum
   * [Bb84](quantum/bb84.py)

project_euler/problem_800/sol1.py

@@ -0,0 +1,65 @@
+"""
+Project Euler Problem 800: https://projecteuler.net/problem=800
+
+An integer of the form p^q q^p with prime numbers p != q is called a hybrid-integer.
+For example, 800 = 2^5 5^2 is a hybrid-integer.
+
+We define C(n) to be the number of hybrid-integers less than or equal to n.
+You are given C(800) = 2 and C(800^800) = 10790
+
+Find C(800800^800800)
+"""
+
+from math import isqrt, log2
+
+
+def calculate_prime_numbers(max_number: int) -> list[int]:
+    """
+    Returns prime numbers below max_number
+
+    >>> calculate_prime_numbers(10)
+    [2, 3, 5, 7]
+    """
+
+    is_prime = [True] * max_number
+    for i in range(2, isqrt(max_number - 1) + 1):
+        if is_prime[i]:
+            for j in range(i**2, max_number, i):
+                is_prime[j] = False
+
+    return [i for i in range(2, max_number) if is_prime[i]]
+
+
+def solution(base: int = 800800, degree: int = 800800) -> int:
+    """
+    Returns the number of hybrid-integers less than or equal to base^degree
+
+    >>> solution(800, 1)
+    2
+
+    >>> solution(800, 800)
+    10790
+    """
+
+    upper_bound = degree * log2(base)
+    max_prime = int(upper_bound)
+    prime_numbers = calculate_prime_numbers(max_prime)
+
+    hybrid_integers_count = 0
+    left = 0
+    right = len(prime_numbers) - 1
+    while left < right:
+        while (
+            prime_numbers[right] * log2(prime_numbers[left])
+            + prime_numbers[left] * log2(prime_numbers[right])
+            > upper_bound
+        ):
+            right -= 1
+        hybrid_integers_count += right - left
+        left += 1
+
+    return hybrid_integers_count
+
+
+if __name__ == "__main__":
+    print(f"{solution() = }")