walk tree code root code node follow direct given code path code destin node destin node reach return param root root tree param path path walk tree messag end path code code object walk tree object root list path path size bv path bv math max integ path valu sv path sv math max integ path valu root walk root bv root bv root successor root sv root path size iter candid root model facad activ messag root root iter thing strang candid root obviou interpret term tree root messag root 