Algorithm 1 Push-Relabel_MaximumFlow_Algorithm [28].

Input: PPI, Capacity = C, N = unique nodes of PPI, start_node = SDN, destination_node = DDN. Output: Maximum flow between SDN and DDN   (1) FOR i = 1 to length [N]:     a. HeightV [i] = 0//HeightV is height of every vertex     b. FlowV [i] = 0//FlowV is the flow of every vertex   (2) HeightV [start_node] = length [N]   (3) FOR i = 1 to length [PPI]:     a. FlowE [i] = 0//FlowE is the flow of every edge in the PPI   (4) V = adjacentVetex[start_node]   (5) FOR i = 1 to length [V]:     a. FlowV [V[i]] = Capacity [V[i]]     b. excessFlow [V[i]] = Capacity [V[i]]   (6) PUSH: FOR i = 1 to length [N]:   If excessFlow [N[i]] ≠ 0: (in the residual graph)      tmpV = adjacentVetex[N[i]]      if HeightV [N[i]] > lowest_height[tmpV]       Push_flow from N[i] to lower height vertices   (7) RELABEL: FOR i = 1 to length [N]:   If excessFlow [N[i]] ≠ 0: (in the residual graph)     tmpV = adjacentVetex[N[i]]     if HeightV [N[i]] ≤ lowest_height[tmpV]      HeightV [N[i]] = minimumHeight[tmp]