47 lines
1.9 KiB
C++
47 lines
1.9 KiB
C++
|
class Graph {
|
|||
|
|
public:
|
|||
|
|
vector<vector<int>> dist;
|
|||
|
|
int num;
|
|||
|
|
Graph(int n, vector<vector<int>>& edges) {
|
|||
|
|
num=n;
|
|||
|
|
dist=vector<vector<int>>(n,vector<int>(n,INT_MAX));//所有端点之间距离初始化为无穷大
|
|||
|
|
for (int i=0;i<n;i++) dist[i][i]=0;//自己到自己的距离为0
|
|||
|
|
int m=edges.size();
|
|||
|
|
for (int i=0;i<m;i++){
|
|||
|
|
dist[edges[i][0]][edges[i][1]]=edges[i][2]; //添加一条边，左端点到右端点的距离为cost
|
|||
|
|
}
|
|||
|
|
for (int k=0;k<n;k++){ //对于每一个端点，看它是否可以作为中间点连接另外两个端点a和b，如果比直接连接ab更近，则更新ab之间的最短距离
|
|||
|
|
for (int i=0;i<n;i++){
|
|||
|
|
for (int j=0;j<n;j++){
|
|||
|
|
if (dist[i][k] != INT_MAX && dist[k][j] != INT_MAX){
|
|||
|
|
dist[i][j] = min (dist[i][j], dist[i][k]+dist[k][j]);
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
void addEdge(vector<int> edge) {
|
|||
|
|
if (edge[2]>dist[edge[0]][edge[1]]) //如果添加的边的权值大于已有最短路径权值，不需要更新dist[][]，直接返回
|
|||
|
|
return;
|
|||
|
|
for (int i=0;i<num;i++){ //对于每一对端点ij，看是否可以通过edge作为中间边连接，比直接连接ij更近，则更新ij之间的最短距离
|
|||
|
|
for (int j=0;j<num;j++){
|
|||
|
|
if (dist[i][edge[0]] != INT_MAX && dist[edge[1]][j] != INT_MAX){
|
|||
|
|
dist[i][j] = min (dist[i][j], dist[i][edge[0]]+dist[edge[1]][j]+edge[2]);
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
int shortestPath(int node1, int node2) {
|
|||
|
|
return dist[node1][node2]==INT_MAX?-1:dist[node1][node2];
|
|||
|
|
}
|
|||
|
|
};
|
|||
|
|
|
|||
|
|
/**
|
|||
|
|
* Your Graph object will be instantiated and called as such:
|
|||
|
|
* Graph* obj = new Graph(n, edges);
|
|||
|
|
* obj->addEdge(edge);
|
|||
|
|
* int param_2 = obj->shortestPath(node1,node2);
|
|||
|
|
*/
|