Fun algorithm-Frog across the river (JAVA)

Frogs cross the river is a very interesting intellectual game, the main idea is as follows: A river between a number of stone spacing, two teams of frogs across the river, each team has 3 frogs, these frogs can only move forward, can not move backwards, and only one frog at a time to move forward. During the move, the frog can move in front of the empty space, not to skip two positions at a time, but can skip the other side a frog into the front of a vacancy. Ask the two teams how to move the frog to use the fewest steps to the opposite shore separately? (→→→-←←←) Maybe 3 frogs are too few, and it's not hard to do it mentally. What if there were 100 frogs?

/*** Frogs cross the river *@authorRubekid **/ Public classRiverfrog { Public Static Final intLeft_frog =-1;  Public Static Final intRight_frog = 1;  Public Static Final intSTONE = 0; Private int[] frogs; Private intZeroindex; Private intlength; Private intStep = 0;  PublicRiverfrog (intNumber ) {Frogs=New int[Number * 2 +1]; Length=frogs.length; Zeroindex= LENGTH/2;  for(inti=0; i< number; i++) {Frogs[i]=Left_frog; } Frogs[zeroindex]=STONE;  for(inti=0; i< number; i++) {frogs[i+ Zeroindex + 1] =Right_frog; }            }         Public voidrun () { while(!ismoveend (Left_frog) | |!ismoveend (Right_frog)) {            intleft = ZeroIndex-1; intright = Zeroindex+1; if(Left>-1 && Right <length) {                if(Frogs[left]! =Frogs[right]) {                    if(Frogs[left] = =Left_frog) {                        if(Left > 0 && frogs[left-1] = = Right_frog) {//If you move right, there are two in the middle                             This. Move (right); }                        Else{                             This. Move (left); }                    }                    Else if(Left > 0 && frogs[left-1]==Left_frog) {                         This. Move (left-1); }                    Else if(Right <= length && frogs[right+1] = =Right_frog) {                         This. Move (right+1); }                }                Else{                    if(Frogs[left] = =Right_frog) {                        if(Left > 0 && frogs[left-1] = =Left_frog) {                             This. Move (left-1); }                        Else if(right+1 < length && frogs[right+1] = =Right_frog) {                             This. Move (right+1); }                        Else if(Frogs[right] = =Right_frog) {                             This. Move (right); }                    }                    Else if(Frogs[right] = =Left_frog) {                        if(right+1 < length && frogs[right+1] = =Right_frog) {                             This. Move (right + 1); }                        Else if(left >0 && frogs[left-1] = =Left_frog) {                             This. Move (left-1); }                        Else if(Frogs[left] = =Left_frog) {                             This. Move (left); }                    }                }            }            Else if(left = =-1){                if(Frogs[right] = = Left_frog && right<length-1){                     This. Move (right+1); }                Else{                     This. Move (right); }            }            Else if(right = =length) {                if(Frogs[left] = = Right_frog && Left > 0){                     This. Move (left-1); }                Else{                     This. Move (left); }}} System.out.println ("Step:" +step); }        Private voidMoveinti) {        inttemp =Frogs[i]; Frogs[i]=Frogs[zeroindex]; Frogs[zeroindex]=temp; Zeroindex=i; Step++;    Print (); }        Private BooleanIsmoveend (intvalue) {        inti=0;intmax=Zeroindex; if(Value = =Left_frog) {i= Zeroindex+1; Max=length; }         for(intJ=i; j<max; J + +){            if(frogs[j]!=value) {                return false; }        }        return true; }        Private voidprint () {StringBuffer StringBuffer=NewStringBuffer ();  for(intfrog:frogs) {            if(frog>-1) {stringbuffer.append ("" +frog + ""); }            Else{stringbuffer.append (Frog+ "    ");    }} System.out.println (Stringbuffer.tostring ()); }}

Fun algorithm-Frog across the river (JAVA)