HDU 3790 最短路径问题 (最短路)

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=3790

简单的最短路问题，这题听说有重边。我用spfa和dijkstra写了一遍，没判重边，速度都差不多。

dijkstra+优先队列：

#include <iostream>
#include <cstdio>
#include <cstring>
#include <queue>
#include <vector>
using namespace std;
const int INF = 1e9 + 7;
struct Node {
    int _node , _dis , _cost;
    bool operator <(const Node &cmp) const {
        if(_dis == cmp._dis)
            return _cost > cmp._cost;
        return _dis > cmp._dis;
    }
};
struct Edge {
    int to , _dis , _cost , next;
}edge[int(2e5 + 5)];
int dis[1005] , cost[1005] , head[1005] , cnt;

inline void add(int u , int v , int _dis , int _cost) {
    edge[cnt].next = head[u];
    edge[cnt].to = v;
    edge[cnt]._cost = _cost;
    edge[cnt]._dis = _dis;
    head[u] = cnt++;
}

void dijkstra(int s) {
    dis[s] = cost[s] = 0;
    priority_queue <Node> que;
    while(!que.empty()) {
        que.pop();
    }
    que.push(Node{s , 0 , 0});
    while(!que.empty()) {
        Node temp = que.top();
        que.pop();
        int u = temp._node;
        if(temp._dis > dis[u])
            continue;
        for(int i = head[u] ; ~i ; i = edge[i].next) {
            int v = edge[i].to;
            if(dis[v] > dis[u] + edge[i]._dis) {
                dis[v] = dis[u] + edge[i]._dis;
                cost[v] = cost[u] + edge[i]._cost;
                que.push(Node{v , dis[v] , cost[v]});
            }
            else if(dis[v] == dis[u] + edge[i]._dis && cost[v] > cost[u] + edge[i]._cost) {
                cost[v] = cost[u] + edge[i]._cost;
                que.push(Node{v , dis[v] , cost[v]});
            }
        }
    }
}

int main()
{
    int n , m , u , v , d , c;
    while(~scanf("%d %d" , &n , &m) && (n || m)) {
        for(int i = 1 ; i <= n ; ++i)
            cost[i] = dis[i] = INF;
        memset(head , -1 , sizeof(head));
        cnt = 0;
        while(m--) {
            scanf("%d %d %d %d" , &u , &v , &d , &c);
            add(u , v , d , c);
            add(v , u , d , c);
        }
        scanf("%d %d" , &u , &v);
        dijkstra(u);
        printf("%d %d
" , dis[v] , cost[v]);
    }
    return 0;
}

spfa：

#include <iostream>
#include <cstdio>
#include <cstring>
#include <vector>
#include <queue>
using namespace std;
const int INF = 1e9 + 7;
typedef pair <int , pair<int , int> > P; //邻接点 长度 花费
int dis[1005] , cost[1005];
vector <P> G[1005];
void spfa(int s) {
    dis[s] = cost[s] = 0;
    queue <int> que;
    while(!que.empty()) {
        que.pop();
    }
    que.push(s);
    while(!que.empty()) {
        int node = que.front();
        que.pop();
        for(int i = 0 ; i < G[node].size() ; ++i) {
            int temp = G[node][i].first;
            if(dis[temp] > dis[node] + G[node][i].second.first) {
                dis[temp] = dis[node] + G[node][i].second.first;
                cost[temp] = cost[node] + G[node][i].second.second;
                que.push(temp);
            }
            else if(dis[temp] == dis[node] + G[node][i].second.first && cost[temp] > cost[node] + G[node][i].second.second) {
                cost[temp] = cost[node] + G[node][i].second.second;
                que.push(temp);
            }
        }
    }
}

int main()
{
    int n , m , u , v , d , c;
    while(~scanf("%d %d" , &n , &m) && (n || m)) {
        for(int i = 1 ; i <= n ; ++i) {
            dis[i] = cost[i] = INF;
            G[i].clear();
            for(int j = i + 1 ; j <= n ; ++j)
                to[i][j] = to[j][i] = INF;
        }
        for(int i = 0 ; i < m ; ++i) {
            scanf("%d %d %d %d" , &u , &v , &d , &c);
            G[u].push_back(P(v , make_pair(d , c)));
            G[v].push_back(P(u , make_pair(d , c)));
        }
        scanf("%d %d" , &u , &v);
        spfa(u);
        printf("%d %d
" , dis[v] , cost[v]);
    }
    return 0;
}