ccf 交通规划

迪杰特斯拉求单源最短路，并且路径权值最小。

这里本来用的是裸的迪杰特斯拉无任何优化的，结果莫名wa，很难受，不过也学习到了一种完美的迪杰特斯拉模板，用的是优先队列，这里纪念一下。

自己的比较乱的代码：

#include <stdio.h>  
#include <string.h>  
#include <string>  
#include <iostream>  
#include <stack>  
#include <queue>  
#include <vector>  
#include <algorithm>  
using namespace std;  
const int inf = 999999999;
struct node{
	int v;
	int d;
	node(int vv=0, int dd=0)
	{
		v=vv; d=dd;
	}
	friend bool operator < (const node a,const node b)
	{
		return a.d > b.d;
	}
}; // 点与边 
int n,m;
int dis[10010];
int cost[10010];
bool book[10010];
vector<node> mmp[10010];
void dij()
{
	priority_queue<node> op;
	memset(book, false, sizeof(book));
	
	for(int i=2; i<=n; i++)
    dis[i] = cost[i] = inf;	
	op.push(node(1,0));
	book[1] = 1;
	while(!op.empty())
	{
       node tmp = op.top(); op.pop();
	   if(!book[tmp.v]) book[tmp.v] = 1;		
	   int len = mmp[tmp.v].size();
	   for(int i=0; i<len; i++)
	   {
	   	  int vv = mmp[tmp.v][i].v;
	   	  if(book[vv])continue;
	   	  if(dis[vv] > dis[tmp.v] + mmp[tmp.v][i].d){dis[vv] = dis[tmp.v] + mmp[tmp.v][i].d;cost[vv]=mmp[tmp.v][i].d;op.push(node(vv,dis[vv]));}
	   	  if(dis[vv] == dis[tmp.v] + mmp[tmp.v][i].d)
	   	  {
	   	     cost[vv] = min(cost[vv],mmp[tmp.v][i].d);	
		  }
	   }		
	}	
	return ;
}
int main()  
{
     cin >> n >> m;
     int a,b,c;
     for(int i=1; i<=m; i++)
     {
     	scanf("%d %d %d",&a, &b, &c);
     	mmp[a].push_back(node(b,c));
     	mmp[b].push_back(node(a,c));
	 }
	 dij();
	 int sum = 0;
	 for(int i=1; i<=n; i++) sum += cost[i];
	 cout << sum << endl;
    return 0;  
}  

这里是大神完美的模板：

#include <iostream>
#include <queue>
#include <vector>

#define NMAX 10005
#define INTMAX 0x7fffffff

using namespace std;

// v表示节点，cost表示出发点到v点的距离
struct Node {
    int v; 
    int cost;
    Node(int vv = 0, int c = 0) {
        v = vv, cost = c;
    }
    // 优先队列将按距离从小到大排列
    friend bool operator<(Node n1, Node n2) {
        return n1.cost > n2.cost;
    }
};

// v表示边的另一端节点，cost表示该边的权重
struct Edge {
    int v;
    int cost;
    Edge(int vv = 0, int c = 0) {
        v = vv, cost = c;
    }
};

vector<Edge>G[NMAX];    // 无向图
bool marked[NMAX];      // D算法中每个顶点仅处理一遍
int disto[NMAX];        // 出发点到某点距离
int costo[NMAX];        // 接通该点需要增加的边的权重
int N, M;

void dijkstra(int s) {
    for (int i = 0; i <= N; i++) {
        costo[i] = disto[i] = INTMAX;//初始化 
        marked[i] = false;
    }
    disto[s] = 0;
    costo[s] = 0;
    priority_queue<Node>pq;     // 保存<v,disto[v]>且按disto[v]升序排列
    pq.push(Node(s, 0));
    marked[0]=true;

    Node tmp;
    while (!pq.empty()) {
        tmp = pq.top();
        pq.pop();
        int v = tmp.v;
        if (!marked[v]) {
            marked[v]=true;
            int len = G[v].size();
            for (int i = 0; i < len; i++) {
                int vv = G[v][i].v;
                if(marked[vv])
                    continue;
                int cost = G[v][i].cost;
                int newdist = disto[v] + cost;
                if (disto[vv] > newdist) {
                    disto[vv] = newdist;
                    costo[vv] = cost;   // 增加的内容
                    pq.push(Node(vv, disto[vv]));
                }
                // 加入点vv时若出现多种距离相同的方案，选取新边最小那个
                if (disto[vv] == newdist) {
                    costo[vv] = min(costo[vv], cost);
                }
            }
        }
    }
}

int main(void) {
    cin >> N >> M;

    int s, e, c;
    for (int i = 0; i < M; i++) {
        cin >> s >> e >> c;
        G[s].push_back(Edge(e, c));//无线图中添加边 
        G[e].push_back(Edge(s, c));
    }
    dijkstra(1);

    // 统计边权重
    int res = 0;
    for (int i = 2; i <= N; i++) {
        res += costo[i];
    }
    cout << res << endl;

    return 0;
}