\documentclass[tikz,border=5pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{decorations.pathreplacing,calligraphy}
\usetikzlibrary{calc}
\usetikzlibrary{shapes.geometric}
\usetikzlibrary{arrows.meta}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{textcomp,amssymb,amsmath,amsthm}
\usepackage{xcolor}
\tikzset{sttriangle/.style={draw=black,fill=white,regular polygon,regular polygon sides=3,minimum size = 0pt,inner sep=1pt}
}\tikzset{stcircle/.style={fill=white,draw=black,circle,inner sep=1pt,minimum size = 1.5em}
}\tikzset{rednode/.style={fill=white,draw=black,circle,inner sep=1pt,minimum size = 1.5em}
}\tikzset{blacknode/.style={text=white,fill=black,draw=black,circle,inner sep=1pt,minimum size = 0.5em}
}\tikzset{splitter/.style={fill=black,circle,inner sep=0pt,minimum size = 4pt}
}\tikzset{term/.style={draw=black,fill=black,rectangle,inner sep=0pt,minimum size=4pt}
}\tikzset{chooser/.style={draw=black,fill=white,circle,inner sep=0pt,minimum size = 4pt}
}\tikzset{saturated/.style={very thick}
}\tikzset{fluid/.style={}
}\tikzset{OutPrio/.tip = {||.}
}
\begin{document}
\begin{tikzpicture}[x=2cm,y=1.5cm,>=latex]
\foreach \n in {1,2,3} {\node[term] (i\n) at (0,\n) {};
\node[term] (o\n) at (3,\n) {};
}\foreach \n/\x/\y in {a/1/0.5,b/1/2.5,c/2/0.5,d/2/2.5} {\node[splitter] (\n) at (\x,\y) {};
}\draw[->,fluid] (i1) -- (a);
\draw[->,fluid] (i2) -- (b);
\draw[->,fluid] (i3) -- (b);
\draw[->,fluid] (a) -- (c);
\draw[->,fluid] (a) -- (d);
\draw[->,fluid] (b) -- (c);
\draw[->,fluid] (b) -- (d);
\draw[->,fluid] (c) -- (o1);
\draw[->,fluid] (d) -- (o2);
\draw[->,fluid] (d) -- (o3);
\draw[->,fluid] (c) .. controls (2.5,-0.33) and (2.5,-0.5) .. (2,-0.5) -- (1,-0.5) .. controls (0.5,-0.5) and (0.5,-0.33) .. (a);
\draw[blue,very thick] ($(i3.center) + (0,0.1)$) -- ($(0.5,2.75) + (0,0.1)$) node[above=-3pt] {$1$};
\draw[blue,line width=0.95pt] ($(0.5,2.75) + (0,0.1)$) .. controls ($(b.center) + (0,0.1)$) .. ($(1.5,2.5) + (0,0.1)$) node[above=-3pt] {$1/2$};
\draw[blue,thick] ($(1.5,2.5) + (0,0.1)$) .. controls ($(d.center) + (0,0.1)$) .. ($(2.5,2.75) + (0,0.1)$);
\draw[blue,thick] ($(2.5,2.75) + (0,0.1)$) -- ($(o3.center) + (0,0.1)$) node[above=-3pt,sloped,pos=0.8] {$1/4$};
\draw[blue,thick] ($(1.5,2.5) + (0,0.1)$) .. controls ($(d.center) + (0,0.1)$) .. ($(2.5,2.25) + (0,0.1)$);
\draw[blue,thick] ($(2.5,2.25) + (0,0.1)$) -- ($(o2.center) + (0,0.1)$) node[above=-3pt,sloped,pos=0.8] {$1/4$};
\draw[blue,line width=0.95pt] ($(0.5,2.75) + (0,0.1)$) .. controls ($(b.center) + (0,0.1)$) .. ($(1.5,1.5) + (0,0.1)$) node[above=-3pt,sloped,pos=0.8] {$1/2$};
\draw[blue,thick] ($(1.5,1.5) + (0,0.1)$) .. controls ($(c.center) + (0,0.1)$) .. ($(2.5,0.75) + (0,0.1)$) node[above=-3pt] {$1/4$};
\draw[blue,thick] ($(2.5,0.75) + (0,0.1)$) -- ($(o1.center) + (0,0.1)$);
\draw[blue,thick] ($(1.5,1.5) + (0,0.1)$) .. controls ($(c.center) + (0,0.1)$) .. (2.2,0.3) .. controls (2.55,-0.23) and (2.6,-0.6) .. (2,-0.6) -- (1,-0.6) node[midway,below=-3pt] {$1/4$} .. controls (0.4,-0.6) and (0.4,-0.23) .. (0.8,0.3) [semithick] .. controls ($(a.center) + (-0.05,+0.03)$) .. ($(1.5,1.5)$) node[pos=0.6,above=-3pt,sloped] {$1/8$};
\draw[blue,thick] (1,-0.6) .. controls (0.4,-0.6) and (0.4,-0.23) .. (0.8,0.3) [semithick] .. controls (0.9,0.4) and ($(a.center) + (0.2,-0.1)$) .. ($(1.5,0.5) - (0,0.1)$) node[below=-3pt] {$1/8$};
\draw[blue,thin] ($(1.5,1.5)$) .. controls ($(d.center) - (0,0.1)$) .. ($(2.5,2.75) - (0,0.1)$) -- ($(o3.center) - (0,0.1)$) node[pos=0.8,below=-3pt,sloped] {\small $1/16$};
\draw[blue,thin] ($(1.5,1.5)$) .. controls ($(d.center) - (0,0.1)$) .. ($(2.5,2.25) - (0,0.1)$) -- ($(o2.center) - (0,0.1)$) node[pos=0.8,below=-3pt,sloped] {\small $1/16$};
\draw[blue,thin] ($(1.5,0.5) - (0,0.1)$) .. controls ($(c.center) - (0,0.1)$) .. ($(2.5,0.75) - (0,0.1)$) -- ($(o1.center) - (0,0.1)$) node[pos=0.8,below=-3pt,sloped] {\small $1/16$};
\draw[blue,thin] ($(1.5,0.5) - (0,0.1)$) .. controls (1.7,0.4) and ($(c.center) - (0,0.1)$) .. (2.12,0.23) .. controls ($(2.24,0.06) - (0,0.1)$) and ($(2.4,-0.5) + (0,0.1)$) .. ($(2,-0.5) + (0,0.1)$);
\draw[blue,very thin,dashed] ($(2,-0.5) + (0,0.1)$) -- ($(1,-0.5) + (0,0.1)$) node[midway,above=-3pt,sloped] {\small $1/16$};
\draw (o1) node[anchor=west] {c};
\draw (o2) node[anchor=west] {b};
\draw (o3) node[anchor=west] {a};
\begin{scope}[xshift=-5cm,x=0.7cm,y=0.7cm]
\foreach \n/\x/\y in {a/0/4,b/-1.5/3,c/1.5/3,g/2.5/2,h/1/1,i/4/1} {\node[splitter,blue] (\n) at (\x,\y) {};
}
\foreach \n/\x/\y in {d/-2.5/2,e/-0.5/2,f/0.5/2,j/0/0,k/2/0,l/3/0} {\node[term,blue] (\n) at (\x,\y) {};
}
\foreach \u/\v in {a/b,a/c} {\draw[blue,line width=0.95pt] (\u) -- (\v) node[sloped,midway,above=-3pt] {$1/2$};
}\foreach \u/\v in {b/d,b/e,c/f,c/g} {\draw[blue,thick] (\u) -- (\v) node[sloped,midway,above=-3pt] {$1/4$};
}\foreach \u/\v in {g/h,g/i} {
\draw[blue,semithick] (\u) -- (\v) node[sloped,midway,above=-3pt] {$1/8$};
}\foreach \u/\v in {h/j,h/k,i/l} {\draw[blue,thin] (\u) -- (\v) node[sloped,midway,above=-3pt] {\small $1/16$};
}\draw[blue,thin] (i) -- (4.5,0.5) [dashed] -- (5,0);
\draw ($(d) - (0,1em)$) node[anchor=base] {a};
\draw ($(e) - (0,1em)$) node[anchor=base] {b};
\draw ($(f) - (0,1em)$) node[anchor=base] {c};
\draw ($(j) - (0,1em)$) node[anchor=base] {a};
\draw ($(k) - (0,1em)$) node[anchor=base] {b};
\draw ($(l) - (0,1em)$) node[anchor=base] {c};
\end{scope}
\end{tikzpicture}
\end{document}