Before revision: Quantum Approximate Optimization Algorithm (QAOA) has been studied widely in the literature, primarily for finding an approximate value of the maximum cut size of a graph. QAOA is composed of a problem hamiltonian and a mixer hamiltonian which are applied alternately for p \geq 1 layers. The circuit for this algorithm requires 2m CNOT gatesin each layer, where m is the number of edges in the graph. CNOT gate is one of the primary sources of error in modern quantum computers.
After revision: Quantum Approximate Optimization Algorithm (QAOA) is studied primarily to find approximate solutions to combinatorial optimization problems. For a graph with n vertices and m edges, a depth p QAOA for the Max-cut problem requires 2\cdot m \cdot p CNOT gates. CNOT is one of the primary sources of error in modern quantum computers.