dijkstra - 堆优化

先看两种对vector 的赋值方法

1 .

int t, n;
struct node{
    int to, cost; 
};
vector<node>edge[1005];

int main() {
    int a, b, c;
    
    while(~scanf("%d%d", &t, &n)){
        for(int i = 1; i <= t; i++){
            scanf("%d%d%d", &a, &b, &c);
            node v;
            v.to = b, v.cost = c;
            edge[a].push_back(v);
            v.to = a, v.cost = c;
            edge[b].push_back(v);     
        }
        for(int i = 1; i <= 5; i++){
            for(int j = 0; j < edge[i].size(); j++){
                node v = edge[i][j];
                printf("%d %d\n", v.to, v.cost);

            }
            printf("@@@@@@@@@@@@@@\n");
         }
        printf("***\n");
    }

    return 0;
}

 2 .

int t, n;
struct node{
    int to, cost; 
    node(int x, int y){
        to = x;
        cost = y;
    }
};
vector<node>edge[1005];

int main() {
    int a, b, c;
    
    while(~scanf("%d%d", &t, &n)){
        for(int i = 1; i <= t; i++){
            scanf("%d%d%d", &a, &b, &c);
            edge[a].push_back(node(b, c));
            edge[b].push_back(node(a, c));
        }
        for(int i = 1; i <= 5; i++){
            for(int j = 0; j < edge[i].size(); j++){
                node v = edge[i][j];
                printf("%d %d\n", v.to, v.cost);
            }
            printf("@@@@@@@@@@@@@@\n");
         }
        printf("***\n");
    }

    return 0;
}

板子 ：

const int inf = 1<<29;
int t, n;

struct node
{
    int to, cost;
    node(int a = 0, int b = 0):to(a), cost(b){}
};
struct pp
{
    friend bool operator< (pp n1, pp n2){
        return n1.c > n2.c;
    }
    int v, c;  // 当前点的位置，点上的值
    pp(int _v = 0, int _c = 0):v(_v), c(_c){}
};
vector<node>edge[1005];
int d[1005];
bool vis[1005];

void dij(){
   
    priority_queue<pp>que;
    memset(vis, false, sizeof(vis));
    for(int i = 1; i <= n; i++) d[i] = inf;
    d[1] = 0;
    
    while(!que.empty()) que.pop();
    que.push(pp(1, d[1]));
    
    while(!que.empty()){
        pp temp = que.top();
        que.pop();
        int u = temp.v;
        if (vis[u]) continue;
        vis[u] =1 ;
        
        for(int i = 0; i < edge[u].size(); i++){
            int to_ = edge[u][i].to;
            int co = edge[u][i].cost;
            if (!vis[to_] && d[u] + co < d[to_]){
                d[to_] = d[u] + co;
                que.push(pp(to_, d[to_]));
            }
        }
    }
}

int main() {
    int a, b, c;
    
    while(~scanf("%d%d", &t, &n)){
        for(int i = 1; i <= 1000; i++){
            edge[i].clear();
        } 
        for(int i = 1; i <= t; i++){
            scanf("%d%d%d", &a, &b, &c);    
            edge[a].push_back(node(b, c));
            edge[b].push_back(node(a, c));
        }
        dij();
        printf("%d\n", d[n]);
    }

    return 0;
}