描述
以邻接表作为存储结构实现，求解从给定源点到给定结束点的最短路径。
输入
从1开始表示第一个节点。
第一行输入：顶点数n(2<=n<=100),边数m(2<=m<=100)
第二行输入有向边：起始点s1，结束点 s2，边权值 w
第三行输入：源点start，终点end
输出
若存在路径，输出路径长度；
若不存在，输出-1。
输入样例
6 8
1 6 100
1 5 30
1 3 10
2 3 5
3 4 50
4 6 10
5 4 20
5 6 60
1 6
输出样例
60
#include
#include
#include
#include
#define maxnum 120
#define INF 10000000
using namespace std;
typedef char VertexType;
//边
typedef struct ArcNode
{
int adjvex;
int weight;
struct ArcNode *nextarc;
}ArcNode;
//顶点
typedef struct VNode
{
VertexType data;
ArcNode *firstarc;
}VNode, AdjList[maxnum];
typedef struct
{
AdjList vertices;//数组
int vexnum, arcnum;
}ALGraph;
//顶点节点，保存id和到源顶点的估算距离，优先队列需要的类型
struct Node
{
int id;//源顶点id
int w;//估算距离
//因要实现最小堆，按升序排列，因而需要重载运算符，重定义优先级，以小为先
friend bool operator < (struct Node a, struct Node b)
{
return a.w > b.w;
}
};
int path[maxnum];
int visited[maxnum] = {0};
Node dist[maxnum];
priority_queueq;
void Dijkstra(ALGraph g, int v0, int n)
{
//初始化
for(int i = 1; i <= n; i++)
{
dist[i].id = i;
dist[i].w = INF;
path[i] = -1; //每个顶点都无父亲节点
visited[i] = 0; //都未找到最短路
}
dist[v0].w = 0;
q.push(dist[v0]);
while(!q.empty())
{
Node cd = q.top();
q.pop();
int u = cd.id;
if(visited[u])
continue;
visited[u] = 1;
ArcNode *p = g.vertices[u].firstarc;
while(p)
{
int tempv = p->adjvex;
int tempw = p->weight;
if(!visited[tempv] && dist[tempv].w > dist[u].w+tempw)
{
dist[tempv].w = dist[u].w+tempw;
path[tempv] = u;
q.push(dist[tempv]);
}
p = p->nextarc;
}
}
}
void CreateALGraph(ALGraph &g, int arc, int vex)
{
g.arcnum = arc;
g.vexnum = vex;
int v1, v2, i, w;
for(i = 1; i <= vex; i++)
{
g.vertices[i].firstarc = NULL;
}
for(i = 1; i <= arc; i++)
{
cin >> v1 >> v2 >> w;
ArcNode *q = (ArcNode*)malloc(sizeof(ArcNode));
q->adjvex = v2;
q->weight = w;
q->nextarc = g.vertices[v1].firstarc;
g.vertices[v1].firstarc = q;
}
}
int DFS(ALGraph g, int i, int j)
{
visited[i] = 1;
ArcNode *p = g.vertices[i].firstarc;
while(p)
{
if(p->adjvex == j)
return 1;
//cout <adjvex])<< endl;
if(!(visited[p->adjvex]) && DFS(g, p->adjvex, j))
return 1;
p = p->nextarc;
}
return 0;
}
int BFS(ALGraph g, int i, int j)
{
queueq;//
q.push(i);
visited[i] = 1;
ArcNode *p;
while(!q.empty())
{
int temp = q.front();
q.pop();
p = g.vertices[temp].firstarc;
while(p)
{
//cout << p->adjvex;
if(p->adjvex == j)
return 1;
if(!(visited[p->adjvex]))
{
visited[p->adjvex] = 1;
q.push(p->adjvex);
}
p = p->nextarc;
}
}
return 0;//返回不可少
}
int main()
{
int m, n;
//顶点，边
cin >> n >> m;
ALGraph g;
CreateALGraph(g, m, n);
// for(int i = 1; i <= n; i++)
// {
// ArcNode *p = g.vertices[i].firstarc;
// cout << "i = " << i << ": ";
// while(p)
// {
// cout << p->adjvex;
// p = p->nextarc;
// }
//cout << endl;
// }
int v0, ve;
cin >> v0 >> ve;
Dijkstra(g, v0, n);
if(dist[ve].w != INF)
cout << dist[ve].w << endl;
else
cout << -1 <
return 0;
}