Compiling principle: Formal conversion into NFA algorithm

Importjava.util.ArrayList;ImportJava.util.Map;ImportJava.util.TreeMap;classedge{Private intu, v; Private Charkey;  PublicEdge (intUintVCharkey) {        Super();  This. u =u;  This. v =v;  This. Key =key; } @Override PublicString toString () {returnU + "+" + V + "" +key; }}classnfa{PrivateString Formal_ceremony;//Regular String    Private intcnt_node=1;//number of record nodes    PrivateMap<integer, integer> Endnode =NewTreemap<integer, integer> ();//each endpoint corresponding to the start nodeArraylist<edge> nodeal =NewArraylist<edge>();  PublicNFA (String formal_ceremony) {Super();  This. Formal_ceremony =Formal_ceremony; }         Public BooleanKernel_way (intFaintLdintRdBooleanIsclosure) {//FA represents the starting point of the interval, the normal interval [ld, RD], and Isclosure indicates whether a closure is found in this interval        if(LD < 0 | | Rd >=formal_ceremony.length ()) {System.out.println ("Normal type is incorrect---an array is out of bounds!"); return false; }        intPre_node =FA; intInbracket = 0;//Judging ' | ' is within brackets         for(intI=ld; i<=rd; ++i) {            if(Formal_ceremony.charat (i) = = ' (') + +Inbracket; Else if(Formal_ceremony.charat (i) = = ') ')--Inbracket; Else if(Formal_ceremony.charat (i) = = ' | ' && 0==inbracket) {                if(!kernel_way (FA, LD, i-1, isclosure))return false; if(!kernel_way (FA, i+1, RD, Isclosure))return false; return true; }        }         for(intI=ld; i<=rd; ++i) {            if(Formal_ceremony.charat (i) = = ' (') {//It's a sub-zone again .//Look for the ' (' matching ') '                intCntleftbracket = 0;//Statistics Traversal process ' (' occurrences, encounters ') ' minus 1                intPosrightbracket =-1;//record matches the ') ' position                intPosleftbracket =i;  for(intj=i+1; j<=rd; ++j) {                    if(Formal_ceremony.charat (j) = = ' (')                        ++Cntleftbracket; Else if(Formal_ceremony.charat (j) = = ') '){                        if(Cntleftbracket = = 0) {Posrightbracket=J;  Break; }                        --Cntleftbracket; }                }                if(Posrightbracket = =-1) {//ErrorSystem.out.println ("Normal type error----brackets mismatch!")); return false; }                intNodefather = 0;//The starting node of the regular type in parentheses                if(posrightbracket+1 <= Rd && Formal_ceremony.charat (posrightbracket+1) = = ' * ') {i= posrightbracket+1;//filter Out "() *"Nodeal.add (NewEdge (Pre_node, ++cnt_node, ' $ '));//indicates that this edge is emptyPre_node =Cnt_node; Nodefather=Cnt_node; Nodeal.add (NewEdge (Pre_node, ++cnt_node, ' $ '));//indicates that this edge is emptyPre_node =Cnt_node; //processing () * Regular type in brackets                    if(!kernel_way (Nodefather, posleftbracket+1, PosRightBracket-1,true))return false; } Else{Nodefather=Pre_node; if(!kernel_way (Nodefather, posleftbracket+1, PosRightBracket-1,false))//for "(101)", as 101                        return false; I=Posrightbracket; }                            } Else{//Single character                if(Formal_ceremony.charat (i) = = ') ')Continue; if(i+1 <= Rd && Formal_ceremony.charat (i+1) = = ' * ') {Nodeal.add (NewEdge (Pre_node, ++cnt_node, ' $ '));//indicates that this edge is emptyPre_node =Cnt_node; Nodeal.add (NewEdge (Pre_node, Pre_node, Formal_ceremony.charat (i)));//itself to one side of itself                    if(I+1==rd &&isclosure) Nodeal.add (NewEdge (Pre_node, FA, ' $ '));//indicates that this edge is empty and is connected to the Father node                    Else{                        if(Endnode.containskey (FA)) Nodeal.add (NewEdge (Pre_node, Endnode.get (FA), ' $ ')); Else{Nodeal.add (NewEdge (Pre_node, ++cnt_node, ' $ '));//indicates that this edge is empty                            if(I==RD) endnode.put (FA, Cnt_node);//record the last node corresponding to the first node in a non-closure state}} Pre_node=Cnt_node; ++i;//Filter *}Else {                    if(I==rd && isclosure) {//It's a closure case.Nodeal.add (NewEdge (Pre_node, FA, Formal_ceremony.charat (i))); } Else{                        if(Endnode.containskey (FA)) Nodeal.add (NewEdge (Pre_node, Endnode.get (FA), Formal_ceremony.charat (i))); Else{Nodeal.add (NewEdge (Pre_node, + +Cnt_node, Formal_ceremony.charat (i))); if(I==RD) endnode.put (FA, Cnt_node);//record the last node corresponding to the first node in a non-closure state}} Pre_node=Cnt_node; }            }        }        return true; }         Public voidOutputnfa () { for(Edge e:nodeal) System.out.println (e); }}/** Convert regular form to NFA **/ Public classTonfa { Public Static voidMain (string[] args) {//String formal_ceremony = "1 (1010*|1 (010) * *) *0";//String formal_ceremony = "1 (0|1) *101";//String formal_ceremony = "0*1* (010) 0*1*";//String formal_ceremony = "(0|1|2) *";//String formal_ceremony = "0|1";//String formal_ceremony = "0|1|2|3";//String formal_ceremony = "(0|1|6) | (2|3) | (4|5) ";//String formal_ceremony = "(0|1) *| (2|3) * ";String formal_ceremony = "((10) | ( 01) *| (0|1)) "; NFA NFA=NewNFA (Formal_ceremony); if(Nfa.kernel_way (1, 0, Formal_ceremony.length ()-1,false) ) Nfa.outputnfa (); }}

Compiling principle: Formal conversion into NFA algorithm