a*算法

#include <stdio.h>
#include <list>
#include <iostream>
using namespace std;

#define max_width 10
#define max_height 10

struct item
{
	int posx;
	int posy;
	item* parent;

	item()
	{
		posx = 0;
		posy = 0;
		parent = 0;
	}
	~item()
	{
		posx = 0;
		posy = 0;
	}
	bool operator == (item& i)
	{
		return (i.posx == this->posx) && (i.posy == this->posy);
	}
};
item* g_begin;
item* g_end;
item* g_current;

list<item*> g_openlist;
list<item*> g_closelist;


int g_map[max_height][max_width] =
{
	1,1,2,2,2,2,2,2,2,2,
	1,2,2,2,2,2,2,2,2,2,
	2,2,2,2,2,2,2,2,2,2,
	2,2,2,1,1,1,1,1,2,2,
	2,2,2,2,2,2,2,1,2,2,
	2,2,2,2,2,2,2,1,2,2,
	2,2,2,2,2,2,2,1,2,2,
	1,1,1,2,2,2,2,2,2,2,
	1,2,2,2,2,2,2,2,2,2,
	2,2,2,2,2,2,1,1,2,2
};

void print_map(int* map,int height,int width)
{
	for (int i = 0;i<height;i++)
	{
		for(int j = 0;j<width;j++)
		{
			if(map[i*width + j] == 1)
			{
				printf("*");
			}
			else if(map[i*width + j] == 2)
			{
				printf("@");
			}
			else
			{
				printf("#");
			}
			if(j == width- 1)
			{
				printf("\n");
			}
		}
	}
}

bool isinlist(item* i,list<item*> q)
{
	list<item*>::iterator iter;
	for (iter = q.begin();iter!=q.end();iter++)
	{
	    item* p = *iter;
		if(*p == *i)
		{
			return true;
		}
	}
	return false;
}


//改节点是否可走
bool valid_path(item* i)
{
	if(g_map[i->posy][i->posx] == 1)
		return false;
	else
		return true;
}

//八个方向遍历，加入open列表
void find_path(item* i, list<item*>& o,list<item*>& c)
{
	if(! i)
		return;
	if(i->posx -1 >= 0 && i->posy -1 >=0 )
	{
		item*  item0 =  new item;
		item0->parent = i;
		item0->posx = i->posx -1;
		item0->posy = i->posy -1;	
		if(!isinlist(item0,o) && !isinlist(item0,c) && valid_path(item0))
		{
			o.push_back(item0);
		}
	}
	if(i->posy - 1 >= 0)
	{
		item*  item1 =  new item;
		item1->parent = i;
		item1->posx = i->posx;
		item1->posy = i->posy -1;
		if(!isinlist(item1,o) && !isinlist(item1,c) && valid_path(item1))
		{
			o.push_back(item1);
		}	
	}
	if(i->posx + 1 < max_width && i->posy  - 1 >= 0) 
	{
		item*  item2 =  new item;
		item2->parent = i;
		item2->posx = i->posx + 1;
		item2->posy = i->posy -1;
		if(!isinlist(item2,o) && !isinlist(item2,c) && valid_path(item2))
		{
			o.push_back(item2);
		}
	}
	if(i->posx - 1  >= 0)
	{
		item*  item3 =  new item;
		item3->parent = i;
		item3->posx = i->posx -1;
		item3->posy = i->posy;
		if(!isinlist(item3,o) && !isinlist(item3,c) && valid_path(item3))
		{
			o.push_back(item3);
		}
	}
	if(i->posx + 1 < max_width)
	{
		item*  item5 =  new item;
		item5->parent = i;
		item5->posx = i->posx +1;
		item5->posy = i->posy ;
		if(!isinlist(item5,o) && !isinlist(item5,c) && valid_path(item5))
		{
			o.push_back(item5);
		}
	}
	if(i->posy + 1 < max_height && i->posx -1 >= 0)
	{
		item*  item6 =  new item;
		item6->parent = i;
		item6->posx = i->posx -1;
		item6->posy = i->posy +1;
		if(!isinlist(item6,o) && !isinlist(item6,c) && valid_path(item6))
		{
			o.push_back(item6);
		}
	}
	if(i->posy + 1 < max_height)
	{
		item*  item7 =  new item;
		item7->parent = i;
		item7->posx = i->posx;
		item7->posy = i->posy +1;
		if(!isinlist(item7,o) && !isinlist(item7,c) && valid_path(item7))
		{
			o.push_back(item7);
		}
	}
	if(i->posx + 1 < max_width && i->posy+1 < max_height)
	{
		item*  item8 =  new item;
		item8->parent = i;
		item8->posx = i->posx +1;
		item8->posy = i->posy +1;
		if(!isinlist(item8,o) && !isinlist(item8,c) && valid_path(item8))
		{
			o.push_back(item8);
		}
	}
}


//估值 
int caculate_score(const item* stp,const item* dst)
{
	return (dst->posx - stp->posx)*(dst->posx - stp->posx) + (dst->posy - stp->posy)*(dst->posy - stp->posy);
}

//找估值最小的节点
item* get_minscore_item(list<item*>& q)
{
	list<item*>::iterator iter;
	item* pmin = NULL;
	int min = 100;
	for (iter = q.begin();iter!=q.end();iter++)
	{
		item* p = *iter;
		if(min > caculate_score(p,g_end))
		{
		    pmin = *iter;
			min  =  caculate_score(pmin,g_end);
		}
	}
	return pmin;
}

void add_item(item* i, list<item*>& q)
{
	list<item*>::iterator iter;
	bool insert = true;
	for (iter = q.begin();iter!=q.end();iter++)
	{
		item* p = *iter;
		if(*p == *i)
		{
			insert = false;
			break;
		}
	}
	if(insert) q.push_back(i);
}

void delete_item(item* i, list<item*>& q)
{
	list<item*>::iterator iter;
	for (iter = q.begin();iter!=q.end();iter++)
	{
	    item* p = *iter;
		if(*p == *i)
		{
			q.erase(iter);
			break;
		}
	}
}


int main(char*,char**)
{
	g_openlist.clear();
	g_begin = new item;
	g_begin->posx = 4;
	g_begin->posy = 9;
	g_end = new item;
	g_end->posx =  6;
	g_end->posy =  2;
	g_current = new item;

	print_map(*g_map,max_height,max_height);
	g_openlist.push_back(g_begin);
	while(g_openlist.size() != 0)
	{
		g_current = get_minscore_item(g_openlist);
		if(*g_current == *g_end)
		{
			while(g_current)
			{	
				g_map[g_current->posy][g_current->posx] = 3;
				cout<<"x:"<<g_current->posx<<"y:"<<g_current->posy<<endl;
				g_current = g_current->parent;
			}
			break;
		}
		else
		{
			delete_item(g_current,g_openlist);
			add_item(g_current,g_closelist);
			find_path(g_current,g_openlist,g_closelist);         
		}
	}
	print_map(*g_map,max_height,max_height);

	return 0;
}