Solve the equation for positive integers $m, n$:
\[\left \lfloor \frac{m^2}n \right \rfloor + \left \lfloor \frac{n^2}m \right \rfloor = \left \lfloor \frac mn + \frac nm \right \rfloor +mn\]
To solve the equation for positive integers \( m \) and \( n \):

\[
\left \lfloor \frac{m^2}{n} \right \rfloor + \left \lfloor \frac{n^2}{m} \right \rfloor = \left \lfloor \frac{m}{n} + \frac{n}{m} \right \rfloor + mn
\]

we will consider two cases: \( m \ge n \) and \( m < n \).

1. **Case 1: \( m \ge n \)**

   Let \( m = kn \) where \( k \ge 1 \) and \( k \in \mathbb{R} \).

   a) **Subcase: \( n > 1 \)**

   We need to analyze the terms in the equation:
   \[
   \left \lfloor \frac{(kn)^2}{n} \right \rfloor + \left \lfloor \frac{n^2}{kn} \right \rfloor = \left \lfloor \frac{kn}{n} + \frac{n}{kn} \right \rfloor + kn \cdot n
   \]

   Simplifying each term:
   \[
   \left \lfloor \frac{k^2 n^2}{n} \right \rfloor = \left \lfloor k^2 n \right \rfloor = k^2 n \quad \text{(since \( k^2 n \) is an integer)}
   \]
   \[
   \left \lfloor \frac{n^2}{kn} \right \rfloor = \left \lfloor \frac{n}{k} \right \rfloor
   \]
   \[
   \left \lfloor \frac{kn}{n} + \frac{n}{kn} \right \rfloor = \left \lfloor k + \frac{1}{k} \right \rfloor
   \]
   \[
   kn \cdot n = k n^2
   \]

   The equation becomes:
   \[
   k^2 n + \left \lfloor \frac{n}{k} \right \rfloor = \left \lfloor k + \frac{1}{k} \right \rfloor + k n^2
   \]

   For \( n > 1 \), we need to check if this equation holds. Notice that:
   \[
   k^2 n + \left \lfloor \frac{n}{k} \right \rfloor \le k^2 n + \frac{n}{k}
   \]
   \[
   \left \lfloor k + \frac{1}{k} \right \rfloor + k n^2 \le k + \frac{1}{k} + k n^2
   \]

   Since \( k^2 n \) and \( k n^2 \) are integers, the equation does not hold for \( n > 1 \).

   b) **Subcase: \( n = 1 \)**

   If \( n = 1 \), the equation simplifies to:
   \[
   \left \lfloor m^2 \right \rfloor + \left \lfloor \frac{1}{m} \right \rfloor = \left \lfloor m + \frac{1}{m} \right \rfloor + m
   \]

   Since \( m \) is a positive integer, \( \left \lfloor m^2 \right \rfloor = m^2 \) and \( \left \lfloor \frac{1}{m} \right \rfloor = 0 \) (for \( m \ge 1 \)).

   The equation becomes:
   \[
   m^2 + 0 = \left \lfloor m + \frac{1}{m} \right \rfloor + m
   \]

   For \( m \ge 1 \), \( \left \lfloor m + \frac{1}{m} \right \rfloor = m \). Thus:
   \[
   m^2 = m + m
   \]
   \[
   m^2 = 2m
   \]
   \[
   m(m - 2) = 0
   \]

   The solutions are \( m = 0 \) or \( m = 2 \). Since \( m \) must be a positive integer, \( m = 2 \).

   Therefore, \( m = 2 \) and \( n = 1 \) is a solution.

2. **Case 2: \( m < n \)**

   Let \( n = km \) where \( k > 1 \) and \( k \in \mathbb{R} \).

   The analysis is similar to Case 1, and we find that no additional solutions exist for \( m < n \).

The final answer is \( \boxed{ (m, n) = (2, 1) } \)