Fix of tikzpicture package warning in the example graph

Fix of tikzpicture package warning in the example graph

text/text.tex

@@ -50,8 +50,7 @@
     child {node (c){$\vdots$}
       child {node [circle,draw] (o) {$\frac{n}{2^k}$}}
       child {node [circle,draw] (p) {$\frac{n}{2^k}$}
-        child [grow=right] {node (q) {$=$} edge from parent[draw=none]
-          child [grow=right] {node (q) {$O_{k = \lg n}(n)$} edge from parent[draw=none]
+          child [grow=right] {node (q) {$ = O_{k = \lg n}(n)$} edge from parent[draw=none]
             child [grow=up] {node (r) {$\vdots$} edge from parent[draw=none]
               child [grow=up] {node (s) {$O_2(n)$} edge from parent[draw=none]
                 child [grow=up] {node (t) {$O_1(n)$} edge from parent[draw=none]
@@ -60,7 +59,6 @@
               }
             }
             child [grow=down] {node (v) {$O(n \cdot \lg n)$}edge from parent[draw=none]}
-          }
         }
       }
     }