class vertex{
// ...
};
我tryng設置此公共屬性作爲私有。
vector<edge> edges;
但這裏
void addedge(int from, int to, int length=-1) {
vertices[from].edges.push_back(edge(to, length));
}
這裏
edge &e = vertices[u].edges[i];
我不明白我怎麼能有機會與像在其他情況下的方法到邊緣。
完整代碼:
#define MAX_VER 1000
#define INFINITE 9999
#include <vector>
#include <queue>
#include <iostream>
using namespace std;
class edge{
private:
int to;
int length;
public:
edge(int to, int length) : to(to), length(length) {}
int getTo(){return to;};
void setTo(int t){to=t;};
int getL(){return length;};
void setL(int l){length=l;};
};
class vertex{
private:
//vector<edge> edges;
int dis;
int prev;
public:
vector<edge> edges;
vector<edge> get_edges(){return edges;}
int getDis(){return dis;};
void setDis(int d){dis=d;};
int getPrev(){return prev;};
void setPrev(int p){prev=p;};
};
class graph{
private:
vertex vertices[MAX_VER];
public:
void reset() {
for (int i=0; i < MAX_VER; i++) {
vertices[i].get_edges().clear();
vertices[i].setDis(INFINITE);
vertices[i].setPrev(-1);
}
}
void addedge(int from, int to, int length=-1) {
vertices[from].edges.push_back(edge(to, length));
}
typedef pair<int, int> pp;
void dijkstra(int source) {
priority_queue<pp, vector<pp>, greater<pp> > q;
vertices[source].setDis(0);
q.push(make_pair(0, source));
while (!q.empty()) {
int u = q.top().second;
int dis = q.top().first;
q.pop();
if (dis > vertices[u].getDis())
continue;
for (int i = 0; i < vertices[u].get_edges().size(); i++) {
edge &e = vertices[u].edges[i];
if (dis + e.getL() < vertices[e.getTo()].getDis()) {
vertices[e.getTo()].setDis(dis + e.getL());
vertices[e.getTo()].setPrev(u);
q.push(make_pair(vertices[e.getTo()].getDis(), e.getTo()));
}
}
}
cout << "Distance from vertex 2 to 4 is: " << vertices[4].getDis() << endl;
}
};
int main() {
graph g;
g.reset();
g.addedge(0, 1, 5);
g.addedge(0, 2, 9);
g.addedge(0, 3, 4);
g.addedge(0, 4, 6);
g.addedge(1, 2, 2);
g.addedge(1, 3, 5);
g.addedge(1, 4, 7);
g.addedge(2, 3, 1);
g.addedge(2, 4, 8);
g.addedge(3, 4, 3);
g.dijkstra(2);
return 0;
}
您的get_edges方法按值返回邊,您希望通過引用返回它們。但是,結果與您將邊緣公開時幾乎相同。我想你真正想要做的是寫入像addEdge和getEdge這樣的方法來處理你的頂點類,而不是公開地公開地暴露它們。 – hynner 2015-04-04 21:39:33
如果您想從類外部訪問邊緣變量,請使用'get_edges'函數。 – 2015-04-04 21:41:32
'vector getEgdes()const'應該做這個工作 –
2015-04-04 21:41:46