C++ 使用邻接矩阵的Dijkstra算法没有找到从每个节点到每个其他节点的正确距离/路径
我正试图编写一个程序,使用邻接矩阵构建一个图,然后使用Dijkstra算法找到从每个节点到其他每个节点的最短路径。我的程序当前无法每次都找到正确的最短路径。我还需要跟踪路径,但我甚至不确定从哪里开始C++ 使用邻接矩阵的Dijkstra算法没有找到从每个节点到每个其他节点的正确距离/路径,c++,algorithm,graph,dijkstra,adjacency-matrix,C++,Algorithm,Graph,Dijkstra,Adjacency Matrix,我正试图编写一个程序,使用邻接矩阵构建一个图,然后使用Dijkstra算法找到从每个节点到其他每个节点的最短路径。我的程序当前无法每次都找到正确的最短路径。我还需要跟踪路径,但我甚至不确定从哪里开始 class GraphD { public: GraphD(); void buildGraph(ifstream &infile); void insertEdge(int from, int to, int distance); void findS
class GraphD
{
public:
GraphD();
void buildGraph(ifstream &infile);
void insertEdge(int from, int to, int distance);
void findShortestPath();
private:
static const int MAXNODES = 101;
static const int infinity = 2147483647;
struct TableType
{
bool visited;
int dist;
int path;
};
int C[MAXNODES][MAXNODES]; // holds adjacency matrix
int size;
TableType T[MAXNODES][MAXNODES]; // for dijkstra's algorithm
};
#include "GraphD.h"
GraphD::GraphD()
{
size = 0;
for(int i = 1; i < MAXNODES; i++)
{
for(int j = 1; j < MAXNODES; j++)
{
C[i][j] = infinity;
T[i][j].dist = infinity;
T[i][j].visited = false;
T[i][j].path = 0;
}
}
}
void GraphD::buildGraph(ifstream &infile)
{
string line;
if(getline(infile, line))
{
size = atoi(line.c_str());
for(int i = 1; i <= size; i++)
{
getline(infile, line);
data[i] = line;
}
int vertex1, vertex2, distance;
while(getline(infile, line))
{
stringstream edge(line);
edge >> vertex1 >> vertex2 >> distance;
if(vertex1 == 0)
break;
insertEdge(vertex1, vertex2, distance);
}
for(int i = 1; i <= size; i++)
{
C[i][i] = 0;
}
}
}
void GraphD::insertEdge(int from, int to, int distance)
{
C[from][to] = distance;
}
void GraphM::findShortestPath()
{
for(int source = 1; source <= size; source++)
{
T[source][source].dist = 0;
for(int i = 1; i <= size; i++)
{
int v = 0;
int shortestDistance = infinity;
for(int j = 1; j <= size; j++)
{
if((C[source][j] < shortestDistance) && !T[source][j].visited)
{
shortestDistance = C[source][j];
v = j;
}
}
T[source][v].visited = true;
for(int w = 1; w <= size; w++)
{
if(!T[v][w].visited)
{
T[v][w].dist = min(T[v][w].dist, T[source][v].dist + C[v][w]);
}
}
}
}
}
将无穷大值设置为1'000'000'000或类似的smth,因为当您使用MAX_INT value时,这里会出现整数溢出
T[v][w].dist = min(T[v][w].dist, T[source][v].dist + C[v][w]);
另外,我认为您应该替换代码的以下部分
if(!T[v][w].visited)
{
T[v][w].dist = min(T[v][w].dist, T[source][v].dist + C[v][w]);
}
到下一个
if(!T[source][w].visited)
{
T[source][w].dist = min(T[source][w].dist, T[source][v].dist + C[v][w]);
}
因为你需要从顶点源找到到顶点W的距离,而不是V。你读过维基百科吗?FindShortPath甚至没有开始尝试实现Dijkstra的算法;我