How to make binary search trees in an easy and straight forward way?

I'm trying to have this tree in LaTeX and I found this helpful response on this site but I easily got lost with all the brackets that are going on and I now have this

Which is achieved by the following code:

\usepackage{tikz-qtree}
\usetikzlibrary{arrows.meta,bending}
\tikzset{every tree node/.style={minimum width=2em,draw,circle},
blank/.style={draw=none},
edge from parent/.style=
{draw, edge from parent path={(\tikzparentnode) -- (\tikzchildnode)}},
level distance=1.5cm}
\begin{tikzpicture}
\Tree
[.51
[.12 ]
[.87
\edge[blank]; \node[blank]{};
\edge[.52
\edge[]; {83}
\edge[blank]; \node[blank]{};
]
[.40
\edge[]; {20}
\edge[blank]; \node[blank]{};
]
]
]
\end{tikzpicture}


I know that someone can easily fix all these brackets for me but I would appreciate another method that is easier, much more, so that I can also do the rest of the trees that I want to make on my own.

i would simplify tree layout as follows:

and in drawing use package forest:

\documentclass[margin=3mm]{standalone}
\usepackage[edges]{forest}

\begin{document}
\begin{forest}
for tree={
grow=south,
circle, draw, minimum size=3ex, inner sep=1pt,
s sep=7mm
}
[51
[12
[1]
[43
[36]
]
]
[87
[52
[83]
]
]
]
\end{forest}
\end{document}


\documentclass[margin=3mm]{standalone}
\usepackage[edges]{forest}

\begin{document}
\begin{forest}
for tree={
grow=south,
circle, draw, minimum size=3ex, inner sep=1pt,
s sep=3mm
}
[51
[12
[1]
[43
[36]
[,no edge, draw=none]
]
]
[87
[52
[,no edge, draw=none]
[83]
]
[,no edge, draw=none]
]
]
\end{forest}
\end{document}

• In a binary search tree, the notions of left child and right child are fundamental, and they kind of disappeared in your implementation. I never used forest before but I think it is possible to make that explicit, would you be so kind and add a correction to your answer? Thanks! – caverac Mar 20 '18 at 13:41
• @caverac, this option is now added. – Zarko Mar 20 '18 at 13:47
• The solution in the addedndum is much much easier to implement and to read compared to what i had. Thanks a lot (+1). – Does it matter Mar 20 '18 at 14:06
• Indeed the easiest syntax ! – Tarass Mar 20 '18 at 14:19

This is a solution using tikz, as an example consider the following tree

To create this code I used

\documentclass[border = 5pt, tikz]{standalone}

\begin{document}
\begin{tikzpicture}[
every node/.style = {minimum width = 2em, draw, circle},
]
\node {51}
child {node {12}}
child {node {87}};
\end{tikzpicture}
\end{document}


In this representation, it is very clear that both 12 and 87 are children of 57. If you want to grow the tree, just keep adding children

\documentclass[border = 5pt, tikz]{standalone}

\begin{document}
\begin{tikzpicture}[
every node/.style = {minimum width = 2em, draw, circle},
level/.style = {sibling distance = 30mm/#1}
]
\node {51}
child {node {12}
child {node {1}}
child {node {43}
child {node {36}}
child {edge from parent[draw = none]}
}
}
child {node {87}
child {node {52}
child {edge from parent[draw = none]}
child {node {83}}
}
child {edge from parent[draw = none]}
};
\end{tikzpicture}
\end{document}


\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{calc}
\begin{document}
\begin{tikzpicture}[%level distance=5mm,
level 1/.style={level distance=10mm,sibling distance=24mm},
level 2/.style={level distance=10mm,sibling distance=16mm},
level 3/.style={level distance=10mm,sibling distance=16mm},
font=\scriptsize,inner sep=2pt,every node/.style={draw,circle,minimum size=3ex}]

\node {51} % root
child {node {12} % first level
child {node{1}} % 2sd level
child {node{43}
child {node{36}} % 3rd level
child[missing]
}
edge from parent }
child   {node {87} % first level
child {node {52} % 2sd level
child[missing] % 3rd level
child {node{83}}
}
child[missing]
} ;
\end{tikzpicture}
\end{document}