关于三只母鸡和三只小鸡过河问题_三只小鸡和三只小虫过河小虫不能比小鸡少-优快云博客

本文通过编程方式解决了一个经典的逻辑谜题——六只鸡过河问题。该问题涉及三只母鸡和三只小鸡如何利用一艘仅能容纳两只鸡的小船安全地从河的一侧到达另一侧。代码使用了回溯法，并详细展示了每一步的操作过程。

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最近找工作闲来无事，看到http://topic.youkuaiyun.com/t/20021206/23/1239072.html问题。

就编了个程序解决这个问题。

三只母鸡，三只小鸡在河东岸，一条小舟每次最多载两只鸡（大小不论）。

条件：

1、母鸡都会划船。

2、只有一只小鸡会划船，其余两只不会。

3、当小鸡母亲不在身边时，其余母鸡就会啄死这只小鸡。

此题目转自http://topic.youkuaiyun.com/t/20021206/23/1239072.html

一个解读是，船上和岸上是不同地方。

程序采用回溯法。在东岸上船尽量上两只鸡。在西岸尽量只上一只鸡。

一下代码在VC6中运行。

头文件 ChickRiver.h

#ifndef _CHICK_RIVER_H #define _CHICK_RIVER_H #define NUMBER_CHICK 6 #define BOAT_CARRY 2 enum {EAST, WEST, RIVER}; enum {TOWEST, TOEAST}; enum {BIG, SMALL}; typedef struct { int id; int type; int relate; bool bDriver; } chick_character; typedef struct tree_node { int chick_pos[NUMBER_CHICK]; //鸡的位置 int boat_pos; //船的位置 int boat_dir; int level; tree_node *pParent; tree_node *pSubtree; tree_node *pNext; //单链表下一个 }tree_node; void init_chick(chick_character *pChick, int index, int type, int relate, bool bDriver); void init_node(tree_node *pNode, tree_node *pParent); void copy_node(tree_node *pNodeDes, tree_node *pNodeSrc); void ReleaseNode(tree_node* pParent); tree_node *CrossRiver(tree_node *pRoot, tree_node *pParent, chick_character *pChick); tree_node *UpBoat_East(tree_node *pRoot, tree_node *pParent, chick_character *pChick); tree_node *UpBoat_West(tree_node *pRoot, tree_node *pParent, chick_character *pChick); tree_node *DownBoat(tree_node *pRoot, tree_node *pParent, chick_character *pChick); void AddSubTree(tree_node* pParent, tree_node* pSubTree); bool IsEaten_node(tree_node *pNode, chick_character*pChick); bool IsRepeat_node(tree_node *pParent, tree_node *pNode); int GetNumInBoat(tree_node *pNode, int *pBoatIndex); void print_node(tree_node *pParent, chick_character *pChick); void print_reault(tree_node *pParent, chick_character *pChick); void print_stack(tree_node *pParent, chick_character *pChick); #endif

文件ChickRiver.cpp

#include "ChickRiver.h" #include <stdio.h> #include <windows.h> #include <stack> int main(int argc, char* argv[]) { //init chick chick_character *pChick = new chick_character[NUMBER_CHICK]; for(int i=0; i<NUMBER_CHICK; i++) { if(i%2==0) { init_chick(pChick+i, i, BIG, i+1, TRUE); } else if(i==1) //the first small chick can driver boat { init_chick(pChick+1, 1, SMALL, i-1, TRUE); } else { //other small chick can't driver boat init_chick(pChick+i, i, SMALL, i-1, FALSE); } } //init node tree_node *pRoot = new tree_node; init_node(pRoot, NULL); //bigin algorithm tree_node *pLeaf = CrossRiver(pRoot, pRoot, pChick); //result if(pLeaf!=NULL) { printf("succeed cross river and /n"); print_stack(pLeaf, pChick); } else { printf("failed cross river and /n"); } //release tree ReleaseNode(pRoot); return 0; } tree_node *CrossRiver(tree_node *pRoot, tree_node *pParent, chick_character *pChick) { //判断是否已经成功 //print_node(pParent, pChick); BOOL bSucc=TRUE; for(int i=0; i<NUMBER_CHICK; i++) { if(pParent->chick_pos[i]!=WEST) { bSucc=FALSE; break; } } if(bSucc) { return pParent; } tree_node *pLeaf = NULL; switch(pParent->boat_pos) { case EAST: { pLeaf = UpBoat_East(pRoot, pParent, pChick); } break; case WEST: { pLeaf = UpBoat_West(pRoot, pParent, pChick); } break; case RIVER: { pLeaf = DownBoat(pRoot, pParent, pChick); } break; default: { printf("wrong in boat position/n"); } } return pLeaf; } /* * init chick */ void init_chick(chick_character *pChick, int index, int type, int relate, bool bDriver) { pChick->id = index; pChick->type = type; pChick->relate = relate; pChick->bDriver = bDriver; } /* * init node */ void init_node(tree_node *pNode, tree_node *pParent) { int i; if(pParent!=NULL) { for(i=0; i<NUMBER_CHICK; i++) { pNode->chick_pos[i] = pParent->chick_pos[i]; } pNode->boat_pos = pParent->boat_pos; pNode->boat_dir = pParent->boat_dir; pNode->pParent = pParent; pNode->level = pParent->level+1; } else { for(i=0; i<NUMBER_CHICK; i++) { pNode->chick_pos[i] = EAST; } pNode->boat_pos = EAST; pNode->boat_dir = TOWEST; pNode->level=0; pNode->pParent = NULL; } pNode->pSubtree = NULL; pNode->pNext = NULL; } /* * copy node */ void copy_node(tree_node *pNodeDes, tree_node *pNodeSrc) { int i; if(pNodeSrc!=NULL) { for(i=0; i<NUMBER_CHICK; i++) { pNodeDes->chick_pos[i] = pNodeSrc->chick_pos[i]; } pNodeDes->boat_pos = pNodeSrc->boat_pos; pNodeDes->boat_dir = pNodeSrc->boat_dir; pNodeDes->pParent = pNodeSrc->pParent; pNodeDes->level = pNodeSrc->level; pNodeDes->pSubtree = pNodeSrc->pSubtree; pNodeDes->pNext = pNodeSrc->pNext; } else { printf("fail copy node for no src/n"); } } /* * release node */ void ReleaseNode(tree_node* pParent) { if(pParent->pSubtree==NULL) { delete pParent; pParent=NULL; } else { tree_node **ppSubTree = &pParent->pSubtree; tree_node *pNodeTemp; while(*ppSubTree!=NULL) { pNodeTemp = *ppSubTree; ppSubTree = &(*ppSubTree)->pNext; ReleaseNode(pNodeTemp); } } } /* * two chick get up a empty boat */ tree_node *UpBoat_Empty_2(tree_node *pRoot, tree_node *pParent, chick_character *pChick, tree_node* pNodeTemp, int boat_dir_new) { tree_node *pLeaf = NULL; int i, j; int boat_pos = pParent->boat_pos; for(i=0; i<NUMBER_CHICK; i++) { for(j=i; j<NUMBER_CHICK; j++) { if(i!=j) { if(pParent->chick_pos[i]==boat_pos&&pParent->chick_pos[j]==boat_pos) { if(pChick[i].bDriver||pChick[j].bDriver) { init_node(pNodeTemp, pParent); pNodeTemp->chick_pos[i] = RIVER; pNodeTemp->chick_pos[j] = RIVER; //printf("is eaten in boat? %d %d/n", i, j); if(!IsEaten_node(pNodeTemp, pChick)) { //printf("no eaten in boat %d %d/n", i, j); pNodeTemp->boat_pos = RIVER; pNodeTemp->boat_dir = boat_dir_new; if(!IsRepeat_node(pRoot, pNodeTemp)) { tree_node *pNodeSub = new tree_node; copy_node(pNodeSub, pNodeTemp); AddSubTree(pParent, pNodeSub); pLeaf = CrossRiver(pRoot, pNodeSub, pChick); if(pLeaf!=NULL) return pLeaf; } } } } } } } return pLeaf; } /* * one chick get up a empty boat */ tree_node *UpBoat_Empty_1(tree_node *pRoot, tree_node *pParent, chick_character *pChick, tree_node* pNodeTemp, int boat_dir_new) { tree_node *pLeaf = NULL; int i; //, j; int boat_pos = pParent->boat_pos; for(i=0; i<NUMBER_CHICK; i++) { if(pParent->chick_pos[i]==boat_pos) { if(pChick[i].bDriver) { init_node(pNodeTemp, pParent); pNodeTemp->chick_pos[i] = RIVER; if(!IsEaten_node(pNodeTemp, pChick)) { pNodeTemp->boat_pos = RIVER; pNodeTemp->boat_dir = boat_dir_new; if(!IsRepeat_node(pRoot, pNodeTemp)) { tree_node *pNodeSub = new tree_node; copy_node(pNodeSub, pNodeTemp); AddSubTree(pParent, pNodeSub); pLeaf = CrossRiver(pRoot, pNodeSub, pChick); if(pLeaf!=NULL) return pLeaf; } } } } } return pLeaf; } /* * one chick get up a no empty boat */ tree_node *UpBoat_1_1(tree_node *pRoot, tree_node *pParent, chick_character *pChick, tree_node* pNodeTemp, int boat_dir_new, int iboat) { tree_node *pLeaf = NULL; int i; //, j; int boat_pos = pParent->boat_pos; for(i=0; i<NUMBER_CHICK; i++) { if(pParent->chick_pos[i]==boat_pos) { if(pChick[iboat].bDriver||pChick[i].bDriver) { init_node(pNodeTemp, pParent); pNodeTemp->chick_pos[i] = RIVER; if(!IsEaten_node(pNodeTemp, pChick)) { pNodeTemp->boat_pos = RIVER; pNodeTemp->boat_dir = boat_dir_new; if(!IsRepeat_node(pRoot, pNodeTemp)) { tree_node *pNodeSub = new tree_node; copy_node(pNodeSub, pNodeTemp); AddSubTree(pParent, pNodeSub); pLeaf = CrossRiver(pRoot, pNodeSub, pChick); if(pLeaf!=NULL) return pLeaf; } } } } } return pLeaf; } /* * no chick get up a no empty boat */ tree_node *UpBoat_1_0(tree_node *pRoot, tree_node *pParent, chick_character *pChick, tree_node* pNodeTemp, int boat_dir_new, int iboat) { tree_node *pLeaf = NULL; if(pChick[iboat].bDriver) { init_node(pNodeTemp, pParent); pNodeTemp->boat_pos = RIVER; pNodeTemp->boat_dir = boat_dir_new; //if(boat_dir_new==TOWEST) printf("chick %d try to back single/n", iboat); if(!IsRepeat_node(pRoot, pNodeTemp)) { //if(boat_dir_new==TOWEST) printf("chick %d try to back single and no repeat/n", iboat); tree_node *pNodeSub = new tree_node; copy_node(pNodeSub, pNodeTemp); AddSubTree(pParent, pNodeSub); pLeaf = CrossRiver(pRoot, pNodeSub, pChick); if(pLeaf!=NULL) return pLeaf; } } return pLeaf; } /* * in east how chick get up boat */ tree_node *UpBoat_East(tree_node *pRoot, tree_node *pParent, chick_character *pChick) { tree_node *pLeaf = NULL; tree_node *pNodeTemp = new tree_node; int boatIndex[BOAT_CARRY]; int numInBoat = GetNumInBoat(pParent, boatIndex); int boat_dir_new = TOWEST; switch(numInBoat) { case 0: { pLeaf = UpBoat_Empty_2(pRoot, pParent, pChick, pNodeTemp, boat_dir_new); } break; case 1: { pLeaf = UpBoat_1_1(pRoot, pParent, pChick, pNodeTemp, boat_dir_new, boatIndex[0]); } break; default: { printf("boat have two chick /n"); } } if(pLeaf==NULL) { switch(numInBoat) { case 0: { pLeaf = UpBoat_Empty_1(pRoot, pParent, pChick, pNodeTemp, boat_dir_new); } break; case 1: { //printf("chick %d can back single/n", boatIndex[0]); pLeaf = UpBoat_1_0(pRoot, pParent, pChick, pNodeTemp, boat_dir_new, boatIndex[0]); } break; default: { printf("boat have two chick /n"); } } } delete pNodeTemp; return pLeaf; } /* * in west how chick get up boat */ tree_node *UpBoat_West(tree_node *pRoot, tree_node *pParent, chick_character *pChick) { // int i, j; tree_node *pLeaf = NULL; tree_node *pNodeTemp = new tree_node; int boatIndex[BOAT_CARRY]; int numInBoat = GetNumInBoat(pParent, boatIndex); int boat_dir_new = TOEAST; // switch(numInBoat) { case 0: { pLeaf = UpBoat_Empty_1(pRoot, pParent, pChick, pNodeTemp, boat_dir_new); } break; case 1: { pLeaf = UpBoat_1_0(pRoot, pParent, pChick, pNodeTemp, boat_dir_new, boatIndex[0]); } break; default: { printf("boat have two chick /n"); } } if(pLeaf==NULL) { switch(numInBoat) { case 0: { pLeaf = UpBoat_Empty_2(pRoot, pParent, pChick, pNodeTemp, boat_dir_new); } break; case 1: { pLeaf = UpBoat_1_1(pRoot, pParent, pChick, pNodeTemp, boat_dir_new, boatIndex[0]); } break; default: { printf("boat have two chick /n"); } } } delete pNodeTemp; return pLeaf; } /* * chick get down boat as many as best */ tree_node *DownBoat(tree_node *pRoot, tree_node *pParent, chick_character *pChick) { tree_node *pLeaf = NULL; tree_node *pNodeTemp = new tree_node; //number chick in boat now and result save in boatIndex. int boatIndex[BOAT_CARRY]; int numInBoat = GetNumInBoat(pParent, boatIndex); //decide next step boat position. int boat_pos; switch(pParent->boat_dir) { case TOWEST: boat_pos= WEST; break; case TOEAST: boat_pos= EAST; break; default: printf("wrong in boat direction/n"); } // switch(numInBoat) { case 1: { //one chick down boat init_node(pNodeTemp, pParent); pNodeTemp->chick_pos[boatIndex[0]] = boat_pos; if(!IsEaten_node(pNodeTemp, pChick)) { //down boat pNodeTemp->boat_pos = boat_pos; if(!IsRepeat_node(pRoot, pNodeTemp)) { //succeed in new node tree_node *pNodeSub = new tree_node; copy_node(pNodeSub, pNodeTemp); AddSubTree(pParent, pNodeSub); pLeaf = CrossRiver(pRoot, pNodeSub, pChick); } } //another state one chick no down and back if(pLeaf==NULL) { pNodeTemp->chick_pos[boatIndex[0]] = RIVER; pNodeTemp->boat_pos = boat_pos; if(!IsRepeat_node(pRoot, pNodeTemp)) { tree_node *pNodeSub = new tree_node; copy_node(pNodeSub, pNodeTemp); AddSubTree(pParent, pNodeSub); pLeaf = CrossRiver(pRoot, pNodeSub, pChick); } } } break; case 2: { //two chick down boat init_node(pNodeTemp, pParent); pNodeTemp->chick_pos[boatIndex[0]] = boat_pos; pNodeTemp->chick_pos[boatIndex[1]] = boat_pos; if(!IsEaten_node(pNodeTemp, pChick)) { pNodeTemp->boat_pos = boat_pos; if(!IsRepeat_node(pRoot, pNodeTemp)) { tree_node *pNodeSub = new tree_node; copy_node(pNodeSub, pNodeTemp); AddSubTree(pParent, pNodeSub); pLeaf = CrossRiver(pRoot, pNodeSub, pChick); } } //one chick down boat if(pLeaf==NULL) { init_node(pNodeTemp, pParent); pNodeTemp->chick_pos[boatIndex[0]] = boat_pos; pNodeTemp->chick_pos[boatIndex[1]] = RIVER; if(!IsEaten_node(pNodeTemp, pChick)) { //下船 pNodeTemp->boat_pos = boat_pos; if(!IsRepeat_node(pRoot, pNodeTemp)) { tree_node *pNodeSub = new tree_node; copy_node(pNodeSub, pNodeTemp); AddSubTree(pParent, pNodeSub); pLeaf = CrossRiver(pRoot, pNodeSub, pChick); } } } //another one chick down boat if(pLeaf==NULL) { //没下船 init_node(pNodeTemp, pParent); pNodeTemp->chick_pos[boatIndex[0]] = RIVER; pNodeTemp->chick_pos[boatIndex[1]] = boat_pos; if(!IsEaten_node(pNodeTemp, pChick)) { //下船 pNodeTemp->boat_pos = boat_pos; if(!IsRepeat_node(pRoot, pNodeTemp)) { tree_node *pNodeSub = new tree_node; copy_node(pNodeSub, pNodeTemp); AddSubTree(pParent, pNodeSub); pLeaf = CrossRiver(pRoot, pNodeSub, pChick); } } } } break; default: printf("wrong number in boat when down %d /n", numInBoat); } delete pNodeTemp; return pLeaf; } /* * add sub tree */ void AddSubTree(tree_node* pParent, tree_node* pSubTree) { tree_node** pEnd = &pParent->pSubtree; if(*pEnd==NULL) { *pEnd = pSubTree; } else { while(*pEnd!=NULL) { pEnd = &((*pEnd)->pNext); } *pEnd = pSubTree; } } /* * is node can exist */ bool IsEaten_node(tree_node *pNode, chick_character*pChick) { int i; int relate; int boatIndex[BOAT_CARRY]; int numInBoat = GetNumInBoat(pNode, boatIndex); if(numInBoat==2) { bool bHaveBig= false; if(pChick[boatIndex[0]].type==BIG||pChick[boatIndex[1]].type==BIG) { bHaveBig = true; } if(bHaveBig) { for(int i=0; i<BOAT_CARRY; i++) { if(pChick[boatIndex[i]].type==SMALL) { relate = pChick[boatIndex[i]].relate; if(pNode->chick_pos[relate]!=RIVER) { return true; } } } } } bool bBigWest=false; //east for(i=0; i<NUMBER_CHICK; i++) { if(pNode->chick_pos[i]==WEST) { if(pChick[i].type==BIG) { bBigWest=true; break; } } } if(bBigWest) { //printf("big in west/n"); for(i=0; i<NUMBER_CHICK; i++) { if(pNode->chick_pos[i]==WEST) { if(pChick[i].type==SMALL) { relate = pChick[i].relate; if(pNode->chick_pos[relate]!=WEST) { return true; } } } } } bool bBigEast=false; //east for(i=0; i<NUMBER_CHICK; i++) { if(pNode->chick_pos[i]==EAST) { if(pChick[i].type==BIG) { bBigEast=true; break; } } } if(bBigEast) { for(i=0; i<NUMBER_CHICK; i++) { if(pNode->chick_pos[i]==EAST) { if(pChick[i].type==SMALL) { relate = pChick[i].relate; if(pNode->chick_pos[relate]!=EAST) { return true; } } } } } return false; } /* * compare two node */ BOOL Compare(tree_node *pNode1, tree_node *pNode2) { BOOL bSame=true; if(pNode1->boat_pos!=pNode2->boat_pos) { bSame = false; } else if(pNode1->boat_dir!=pNode2->boat_dir) { bSame = false; } else { for(int i=0; i<NUMBER_CHICK; i++) { if(pNode1->chick_pos[i]!=pNode2->chick_pos[i]) { bSame = false; break; } } } return bSame; } /* * is a node is repeat */ bool IsRepeat_node(tree_node *pParent, tree_node *pNode) { bool bSame=false; if(Compare(pParent, pNode)) { bSame = true; } else { tree_node **ppSubTree = &pParent->pSubtree; while(*ppSubTree!=NULL) { bSame = IsRepeat_node(*ppSubTree, pNode); if(bSame) { goto end; } //ppSubTree = &(*ppSubTree)->pSubtree; ppSubTree = &(*ppSubTree)->pNext; } } end: return bSame; } /* * get state in boat now */ int GetNumInBoat(tree_node *pNode, int *pBoatIndex) { for(int i=0; i<BOAT_CARRY; i++) { pBoatIndex[i]=-1; } int numBoat=0; for(i=0; i<NUMBER_CHICK; i++) { if(pNode->chick_pos[i]==RIVER) { pBoatIndex[numBoat] = i; numBoat++; } } return numBoat; } /* * show mid reault */ void print_node(tree_node *pParent, chick_character *pChick) { // static count=0; // printf("level=%d count=%d/n", pParent->level, count); // count++; printf("step=%d/n", pParent->level); printf("EAST:"); for(int i=0; i<NUMBER_CHICK; i++) { if(pParent->chick_pos[i]==EAST) { if(pChick[i].type==BIG) printf("id=%d BIG, ", i); else printf("id=%d SMALL, ", i); } } switch(pParent->boat_pos) { case EAST: printf("/nBOAT:"); break; case WEST: printf("/n/n/nBOAT:"); break; case RIVER: printf("/n/nBOAT:"); break; } for(i=0; i<NUMBER_CHICK; i++) { if(pParent->chick_pos[i]==RIVER) { if(pChick[i].type==BIG) printf("id=%d BIG, ", i); else printf("id=%d SMALL, ", i); } } switch(pParent->boat_pos) { case EAST: printf("/n/n/nWEST:"); break; case WEST: printf("/nWEST:"); break; case RIVER: printf("/n/nWEST:"); break; } for(i=0; i<NUMBER_CHICK; i++) { if(pParent->chick_pos[i]==WEST) { if(pChick[i].type==BIG) printf("id=%d BIG, ", i); else printf("id=%d SMALL, ", i); } } printf("/n"); switch(pParent->boat_pos) { case EAST: { printf("boat in east/n"); } break; case WEST: { printf("boat in west/n"); } break; case RIVER: { if(pParent->boat_dir==TOEAST) { printf("boat in river to east /n"); } else { printf("boat in river to west /n"); } } break; } printf("===================/n"); // getchar(); } /* * printf last reault use stack for normal order */ void print_stack(tree_node *pNode, chick_character *pChick) { using std::stack; stack <tree_node*> aStack; aStack.push(pNode); tree_node *pParent = pNode->pParent; while(pParent!=NULL) { aStack.push(pParent); pParent = pParent->pParent; } tree_node *pNodeTemp; while(!aStack.empty()) { pNodeTemp = aStack.top(); print_node(pNodeTemp, pChick); aStack.pop(); } } /* * printf last reault in reverse order */ void print_reault(tree_node *pParent, chick_character *pChick) { static int count=0; printf("===================step:%d/n", count); count++; printf("EAST:"); //if(pParent->boat_pos==EAST) printf("boat; "); for(int i=0; i<NUMBER_CHICK; i++) { if(pParent->chick_pos[i]==EAST) { if(pChick[i].type==BIG) printf("id=%d BIG, ", i); else printf("id=%d SMALL, ", i); } } printf("/nBOAT:"); //if(pParent->boat_pos==RIVER) printf("boat "); for(i=0; i<NUMBER_CHICK; i++) { if(pParent->chick_pos[i]==RIVER) { if(pChick[i].type==BIG) printf("id=%d BIG, ", i); else printf("id=%d SMALL, ", i); } } printf("/nWEST:"); //if(pParent->boat_pos==WEST) printf("boat "); for(i=0; i<NUMBER_CHICK; i++) { if(pParent->chick_pos[i]==WEST) { if(pChick[i].type==BIG) printf("id=%d BIG, ", i); else printf("id=%d SMALL, ", i); } } printf("/n"); switch(pParent->boat_pos) { case EAST: { printf("boat in east/n"); } break; case WEST: { printf("boat in west/n"); } break; case RIVER: { if(pParent->boat_dir==TOEAST) { printf("boat in river to east /n"); } else { printf("boat in river to west /n"); } } break; } printf("===================/n"); if(pParent->pParent!=NULL) print_reault(pParent->pParent, pChick); }

结果：

succeed cross river and

step=0

EAST:id=0 BIG, id=1 SMALL, id=2 BIG, id=3 SMALL, id=4 BIG, id=5 SMALL,

BOAT:

WEST:

boat in east

===================

step=1

EAST:id=2 BIG, id=3 SMALL, id=4 BIG, id=5 SMALL,

BOAT:id=0 BIG, id=1 SMALL,

WEST:

boat in river to west

===================

step=2

EAST:id=2 BIG, id=3 SMALL, id=4 BIG, id=5 SMALL,

BOAT:

WEST:id=0 BIG, id=1 SMALL,

boat in west

===================

step=3

EAST:id=2 BIG, id=3 SMALL, id=4 BIG, id=5 SMALL,

BOAT:id=0 BIG,

WEST:id=1 SMALL,

boat in river to east

===================

step=4

EAST:id=0 BIG, id=2 BIG, id=3 SMALL, id=4 BIG, id=5 SMALL,

BOAT:

WEST:id=1 SMALL,

boat in east

===================

step=5

EAST:id=0 BIG, id=4 BIG, id=5 SMALL,

BOAT:id=2 BIG, id=3 SMALL,

WEST:id=1 SMALL,

boat in river to west

===================

step=6

EAST:id=0 BIG, id=4 BIG, id=5 SMALL,

BOAT:id=2 BIG,

WEST:id=1 SMALL, id=3 SMALL,

boat in west

===================

step=7

EAST:id=0 BIG, id=4 BIG, id=5 SMALL,

BOAT:id=2 BIG,

WEST:id=1 SMALL, id=3 SMALL,

boat in river to east

===================

step=8

EAST:id=0 BIG, id=2 BIG, id=4 BIG, id=5 SMALL,

BOAT:

WEST:id=1 SMALL, id=3 SMALL,

boat in east

===================

step=9

EAST:id=4 BIG, id=5 SMALL,

BOAT:id=0 BIG, id=2 BIG,

WEST:id=1 SMALL, id=3 SMALL,

boat in river to west

===================

step=10

EAST:id=4 BIG, id=5 SMALL,

BOAT:

WEST:id=0 BIG, id=1 SMALL, id=2 BIG, id=3 SMALL,

boat in west

===================

step=11

EAST:id=4 BIG, id=5 SMALL,

BOAT:id=1 SMALL,

WEST:id=0 BIG, id=2 BIG, id=3 SMALL,

boat in river to east

===================

step=12

EAST:id=4 BIG, id=5 SMALL,

BOAT:id=1 SMALL,

WEST:id=0 BIG, id=2 BIG, id=3 SMALL,

boat in east

===================

step=13

EAST:id=4 BIG, id=5 SMALL,

BOAT:id=1 SMALL,

WEST:id=0 BIG, id=2 BIG, id=3 SMALL,

boat in river to west

===================

step=14

EAST:id=4 BIG, id=5 SMALL,

BOAT:id=1 SMALL,

WEST:id=0 BIG, id=2 BIG, id=3 SMALL,

boat in west

===================

step=15

EAST:id=4 BIG, id=5 SMALL,

BOAT:id=0 BIG, id=1 SMALL,

WEST:id=2 BIG, id=3 SMALL,

boat in river to east

===================

step=16

EAST:id=0 BIG, id=1 SMALL, id=4 BIG, id=5 SMALL,

BOAT:

WEST:id=2 BIG, id=3 SMALL,

boat in east

===================

step=17

EAST:id=1 SMALL, id=5 SMALL,

BOAT:id=0 BIG, id=4 BIG,

WEST:id=2 BIG, id=3 SMALL,

boat in river to west

===================

step=18

EAST:id=1 SMALL, id=5 SMALL,

BOAT:

WEST:id=0 BIG, id=2 BIG, id=3 SMALL, id=4 BIG,

boat in west

===================

step=19

EAST:id=1 SMALL, id=5 SMALL,

BOAT:id=0 BIG,

WEST:id=2 BIG, id=3 SMALL, id=4 BIG,

boat in river to east

===================

step=20

EAST:id=1 SMALL, id=5 SMALL,

BOAT:id=0 BIG,

WEST:id=2 BIG, id=3 SMALL, id=4 BIG,

boat in east

===================

step=21

EAST:id=5 SMALL,

BOAT:id=0 BIG, id=1 SMALL,

WEST:id=2 BIG, id=3 SMALL, id=4 BIG,

boat in river to west

===================

step=22

EAST:id=5 SMALL,

BOAT:

WEST:id=0 BIG, id=1 SMALL, id=2 BIG, id=3 SMALL, id=4 BIG,

boat in west

===================

step=23

EAST:id=5 SMALL,

BOAT:id=1 SMALL,

WEST:id=0 BIG, id=2 BIG, id=3 SMALL, id=4 BIG,

boat in river to east

===================

step=24

EAST:id=1 SMALL, id=5 SMALL,

BOAT:

WEST:id=0 BIG, id=2 BIG, id=3 SMALL, id=4 BIG,

boat in east

===================

step=25

EAST:

BOAT:id=1 SMALL, id=5 SMALL,

WEST:id=0 BIG, id=2 BIG, id=3 SMALL, id=4 BIG,

boat in river to west

===================

step=26

EAST:

BOAT:

WEST:id=0 BIG, id=1 SMALL, id=2 BIG, id=3 SMALL, id=4 BIG, id=5 SMALL,

boat in west

===================