HDU-2544 最短路（dijkstra 邻接矩阵存图、链式前向星存图、链式前向星+优先队列）

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关于链式前向星的博客：https://blog.csdn.net/acdreamers/article/details/16902023

链式前向星+优先队列

#include <iostream>
#include <cstring>
#include <cstdio>
#include <queue>
using namespace std;
const int N = 1e4+5;
const int Inf = 0x3f3f3f3f;
int vis[N],dis[N];
int Head[N];
int n,m,cnt;

struct node{
    int to,w;
    int Next;
    bool operator < (const node &a) const{
        return a.w < w;
    }
} Edge[N],Now,Next;

void init() {
    memset(Head,-1,sizeof(Head));
    cnt = 0;
}

void Add(int u,int v,int w){
    Edge[cnt].to = v;
    Edge[cnt].w = w;
    Edge[cnt].Next = Head[u];
    Head[u] = cnt ++;
}

void dijkstra(int s){
    memset(dis,0x3f,sizeof(dis));
    memset(vis,0,sizeof(vis));
    dis[s] = 0;
    // vis[s] = 1;
    priority_queue<node> q;
    Now.to = s;
    q.push(Now);
    while(!q.empty()){
        Now = q.top();
        q.pop();
        s = Now.to;
        if(vis[s])  continue;
        vis[s] = 1;
        for(int i=Head[s]; ~i; i = Edge[i].Next){
            int v = Edge[i].to;
            if(!vis[v] && dis[v] > dis[s] + Edge[i].w){
                dis[v] = dis[s] + Edge[i].w;
                Next.to = v;
                Next.w = dis[v];
                q.push(Next);
            }
        }
    }
    printf("%d\n",dis[n]);
}

int main(){
    while(~scanf("%d%d",&n,&m),(n && m)){
        init();
        for(int i=0;i<m;i++){
            int u,v,w;
            scanf("%d%d%d",&u,&v,&w);
            Add(u,v,w);
            Add(v,u,w);
        }
        dijkstra(1);
    }

    return 0;
}

---

链式前向星存图

#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;
typedef long long ll;
const int N = 1e4+10;
const int Inf = 0x3f3f3f3f;
int Head[N];
int vis[N],dis[N];
int n,m,cnt;

struct node{
    int to;
    int w;
    int Next;
} Edge[N];

void init(){
    memset(Head,-1,sizeof(Head));
    cnt = 0;
}

void Add(int u,int v,int w){
    Edge[cnt].to = v;
    Edge[cnt].w = w;
    Edge[cnt].Next = Head[u];
    Head[u] = cnt++;
}

void dijkstra(int s){
    memset(dis,Inf,sizeof(dis));
    memset(vis,0,sizeof(vis));
    vis[s] = 1;
    dis[s] = 0;
    for(int i = Head[s]; ~i; i = Edge[i].Next){
        int v = Edge[i].to, w = Edge[i].w;
        dis[v] = w;
    }
    for(int i=1;i<n;i++){
        int Min = Inf;
        for(int j=1;j<=n;j++){
            if(!vis[j] && Min > dis[j]){
                Min = dis[j];
                s = j;
            }
        }
        vis[s] = 1;
        for(int j=Head[s]; ~j ;j = Edge[j].Next){
            int v = Edge[j].to, w = Edge[j].w;
            if(!vis[v] && dis[v] > dis[s] + w){
                dis[v] = dis[s] + w;
            }
        }
    }
    printf("%d\n", dis[n]);
}

int main(){
    while(~scanf("%d%d",&n,&m),(n && m)){
        init();
        int u,v,w;
        for(int i=1;i<=m;i++){
            scanf("%d%d%d",&u,&v,&w);
            Add(u,v,w);
            Add(v,u,w);
        }
        dijkstra(1);
    }

    return 0;
}

---

邻接矩阵存图：

#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;
const int N = 1e3+10;
const int Inf = 0x3f3f3f3f;
int Map[N][N],dis[N],vis[N];
int n,m;
int u,v,w;

void init(){
    for(int i=1;i<=n;i++){
        for(int j=1;j<=n;j++){
            if(i == j)  Map[i][j] = 0;
            else Map[i][j] = Inf;
        }
    }
}

void dijkstra(){
    int s,Min;
    for(int i=1;i<=n;i++){
        dis[i] = Map[1][i];
    }
    memset(vis,0,sizeof(vis));
    vis[1] = 1;
    for(int i=1;i<n;i++){
        Min = Inf;
        for(int j=1;j<=n;j++){
            if(!vis[j] && Min > dis[j]){
                Min = dis[j];
                s = j;
            }
        }
        vis[s] = 1;
        for(int j=1;j<=n;j++){
            if(!vis[j] && dis[j] > dis[s] + Map[s][j]){
                dis[j] = dis[s] + Map[s][j];
            }
        }
    }
    printf("%d\n",dis[n]);
}

int main(){
    while(~scanf("%d%d",&n,&m),(n && m)){
        init();
        for(int i=1;i<=m;i++){
            scanf("%d%d%d",&u,&v,&w);
            if(Map[u][v] > w){
                Map[u][v] = Map[v][u] = w;
            }
        }
        dijkstra();
    }

    return 0;
}