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A-Star算法是一种静态路网中求解最短路径最有效的直接搜索方法
其实百科有
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咳咳，直接上代码。各种注释也算是有助理解了，毕竟这还是抄的~
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// A*寻路算法.cpp : 定义控制台应用程序的入口点。
// Win32控制台程序
#include <math.h>
#include <list>
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using namespace std;
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/*
把地图当成一个个的格子
公式：F=G+H
F：相对路径长度
G：从起点沿着产生的路径，移动到指定点的耗费（路径长度）
H：预估值，从指定的格子移动到终点格子的预计耗费
使用两个表来保存相关数据
启动列表：有可能将要经过的点存到启动列表
关闭列表：不会再被遍历的点
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步骤
1、将起点格子加入启动列表中
2、在启动列表中查找权值（F值）最小的格子
3、查找它周围的能走的格子
4、把这些格子加入启动列表中，已经在启动或关闭列表中的格子不用加入
5、把这些加入启动列表的格子的"父格子"设为当前格子
6、再把当前格子从启动列表中删除，加入关闭列表中
7、如果终点在启动列表中，则找到路径，退出流程，不进行第9步
8、如果启动列表中没有格子了，说明没有找到路径，退出流程，不进行第9步
9、跳转第2步
*/
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// 0：可行走的点
// 1：阻挡点
// 2：路径
// 3：起点
// 4：终点
int g_PathLattice[10][10] =
{
????{ 0,0,0,0,0,0,0,0,0,0 },
????{ 0,0,0,0,0,0,0,0,0,0 },
????{ 0,0,0,0,0,0,0,0,0,0 },
????{ 0,0,0,0,1,0,0,0,0,0 },
????{ 0,0,3,0,1,0,4,0,0,0 },
????{ 0,0,0,0,1,0,0,0,0,0 },
????{ 0,0,0,0,0,0,0,0,0,0 },
????{ 0,0,0,0,0,0,0,0,0,0 },
????{ 0,0,0,0,0,0,0,0,0,0 },
????{ 0,0,0,0,0,0,0,0,0,0 },
};
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struct Node
{
????int row; // 行
????int rank; // 列
????int f;
????int g;
????int h;
????Node * pParent; // 当前结点路径的前一个结点（父格子）
};
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#define LatticeLen 10 // 格子边长
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// 函数前向声明
int Distance(int row1, int rank1, int row2, int rank2);
bool IsNodeInList(Node * pNode, list<Node *> list);
Node * GetNearestNode(list<Node *> list, Node * Rec);
void GetNearNodeList(Node * pNode, list<Node *> & listNear,
????list<Node *> listStart, list<Node *> listEnd, Node * pEndNode);
void EraseFromList(Node * pNode, list<Node *> & listStart);
void ClearList(list<Node *> nodeList);
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int main()
{
????// 起点
????int rowStart;
????int rankStart;
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????// 终点
????int rowEnd;
????int rankEnd;
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????// 查找起点和终点的位置
????for (int i = 0; i < 10; i++)
????{
????????for (int j = 0; j < 10; j++)
????????{
????????????if (g_PathLattice[i][j] == 3)
????????????{
????????????????rowStart = i;
????????????????rankStart = j;
????????????}
????????????if (g_PathLattice[i][j] == 4)
????????????{
????????????????rowEnd = i;
????????????????rankEnd = j;
????????????}
????????}
????}
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????// 起点
????Node * nodeStart = new Node;
????nodeStart->row = rowStart;
????nodeStart->rank = rankStart;
????nodeStart->g = 0;
????nodeStart->h = Distance(rowStart, rankStart, rowEnd, rankEnd);
????nodeStart->f = nodeStart->h;
????nodeStart->pParent = nullptr;
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????// 终点
????Node * nodeEnd = new Node;
????nodeEnd->row = rowEnd;
????nodeEnd->rank = rankEnd;
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????// 定义启动列表和关闭列表
????list<Node *> listStart;
????list<Node *> listEnd;
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????// 把起点加入启动列表
????listStart.push_back(nodeStart);
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????// 当前结点
????Node * pNowNode = nullptr;
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????// 如果终点在启动列表中，则已经找到路径，退出循环
????while (!IsNodeInList(nodeEnd, listStart))
????{
????????Node * Rec = nullptr;
????????// 查找权值最小的格子作为当前点
????????pNowNode = GetNearestNode(listStart, Rec);
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????????// 如果没有找到，则说明没有路径
????????if (pNowNode == nullptr)
????????{
????????????break;
????????}
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????????// 存放当前格子周围能加入启动列表的格子
????????list<Node *> listNear;
????????GetNearNodeList(pNowNode, listNear, listStart, listEnd, nodeEnd);
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????????// 将当前结点加入关闭列表中
????????listEnd.push_back(pNowNode);
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????????// 将当前结点从启动列表中删除
????????EraseFromList(pNowNode, listStart);
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????????// 将周围点加入启动列表中
????????for (list<Node *>::iterator it = listNear.begin();
????????????it != listNear.end(); it++)
????????{
????????????listStart.push_back(*it);
????????}
????}
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????if (pNowNode == nullptr)
????{
????????printf("路径不存在\n");
????????ClearList(listStart);
????????ClearList(listEnd);
????????delete nodeEnd;
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????????return 0;
????}
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????// 在启动列表中找到终点
????Node * pNodeFind = nullptr;
????for (list<Node *>::iterator it = listStart.begin();
????????it != listStart.end(); it++)
????{
????????if ((*it)->row == nodeEnd->row &&
????????????(*it)->rank == nodeEnd->rank)
????????{
????????????pNodeFind = (*it);
????????????break;
????????}
????}
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????while (pNodeFind)
????{
????????g_PathLattice[pNodeFind->row][pNodeFind->rank] = 2;
????????pNodeFind = pNodeFind->pParent;
????}
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????for (int i = 0; i < 10; i++)
????{
????????for (int j = 0; j < 10; j++)
????????{
????????????if (g_PathLattice[i][j] == 0)
????????????{
????????????????printf("^ ");
????????????}
????????????else if (g_PathLattice[i][j] == 1)
????????????{
????????????????printf("* ");
????????????}
????????????else if (g_PathLattice[i][j] == 2)
????????????{
????????????????printf("# ");
????????????}
????????}
????????printf("\n");
????}
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????ClearList(listStart);
????ClearList(listEnd);
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????delete nodeEnd;
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????return 0;
}
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int Distance(int row1, int rank1, int row2, int rank2)
{
????// 格子的中点坐标
????int x1 = rank1 * LatticeLen + LatticeLen / 2;
????int y1 = row1 * LatticeLen + LatticeLen / 2;
????int x2 = rank2 * LatticeLen + LatticeLen / 2;
????int y2 = row2 * LatticeLen + LatticeLen / 2;
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????return (int)sqrt((double)((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2)));
}
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bool IsNodeInList(Node * pNode, list<Node *> NodeList)
{
????for (list<Node *>::iterator it = NodeList.begin();
????????it != NodeList.end(); it++)
????{
????????if (pNode->row == (*it)->row && pNode->rank == (*it)->rank)
????????{
????????????return true;
????????}
????}
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????return false;
}
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Node * GetNearestNode(list<Node *> NodeList, Node * Rec)
{
????int tempF = 1000000;
????for (list<Node *>::iterator it = NodeList.begin();
????????it != NodeList.end(); it++)
????{
????????if ((*it)->f < tempF)
????????{
????????????Rec = *it;
????????????tempF = (*it)->f;
????????}
????}
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????return Rec;
}
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void GetNearNodeList(Node * pNode, list<Node *> & listNear,
????list<Node *> listStart, list<Node *> listEnd, Node * pEndNode)
{
????// 将结点旁边的8个点加入到listNear中
????// 在启动或关闭列表中的点不能加入listNear
????// 阻挡点不能加入listNear
????for (int i = -1; i <= 1; i++)
????{
????????for (int j = -1; j <= 1; j++)
????????{
????????????if (i == 0 && j == 0)
????????????{
????????????????// 自己格子
????????????????continue;
????????????}
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????????????int rowTemp = pNode->row + i;
????????????int rankTemp = pNode->rank + j;
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????????????if (rowTemp < 0 || rankTemp < 0 || rowTemp > 9 || rankTemp > 9)
????????????{
????????????????// 越界
????????????????continue;
????????????}
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????????????if (g_PathLattice[rowTemp][rankTemp] == 1)
????????????{
????????????????// 阻挡点
????????????????continue;
????????????}
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????????????Node node;
????????????node.row = rowTemp;
????????????node.rank = rankTemp;
????????????if (IsNodeInList(&node, listStart))
????????????{
????????????????// 在启动列表中
????????????????continue;
????????????}
????????????if (IsNodeInList(&node, listEnd))
????????????{
????????????????// 在关闭列表中
????????????????continue;
????????????}
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????????????Node * pNearNode = new Node;
????????????pNearNode->g = pNode->g + Distance(pNode->row, pNode->rank, rowTemp, rankTemp);
????????????pNearNode->h = Distance(rowTemp, rankTemp, pEndNode->row, pEndNode->rank);
????????????pNearNode->f = pNearNode->g + pNearNode->h;
????????????pNearNode->row = rowTemp;
????????????pNearNode->rank = rankTemp;
????????????pNearNode->pParent = pNode;
????????????listNear.push_back(pNearNode);
????????}
????}
}
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void EraseFromList(Node * pNode, list<Node *> & listStart)
{
????for (list<Node *>::iterator it = listStart.begin();
????????it != listStart.end(); it++)
????{
????????if (pNode->row == (*it)->row && pNode->rank == (*it)->rank)
????????{
????????????listStart.erase(it);
????????????return;
????????}
????}
}
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void ClearList(list<Node *> nodeList)
{
????for (list<Node *>::iterator it = nodeList.begin();
????????it != nodeList.end(); it++)
????{
????????delete *it;
????}
}
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原文地址：http://www.cnblogs.com/recordprogram/p/5660473.html
