hdu 1874 dijkstra 队列实现 比数组高效特别在稀疏图

参考 http://blog.csdn.net/zhuyingqingfen/article/details/6370561
刘汝佳白皮书

#include<stdio.h>

#include<queue>

#include<iostream>

#include<vector>

using namespace std;

#define N 2100

#define inf 1000000000

int n,m;

struct node {

int u,v,w,next;

}bian
;

int yong,head
;

void creat(int u,int v,int w) {

bian[yong].u=u;

bian[yong].v=v;

bian[yong].w=w;

bian[yong].next=head[u];

head[u]=yong++;

}

void Dcreat(int u,int v,int w) {

creat(u,v,w);

creat(v,u,w);

}

int dijkstra(int u,int end) {

int dis
,i,j,visit
;

memset(visit,0,sizeof(visit));

for(i=0;i<n;i++)

dis[i]=inf;

dis[u]=0;

typedef pair<int ,int >p;//pair 定义了自己的排序规则--先比较第一维，相等才比较第二维

priority_queue<p,vector<p>,greater<p> >q;

q.push(make_pair(dis[u],u));

while(!q.empty()) {

p cur=q.top();

j=cur.second;

q.pop();

if(visit[j])continue;

visit[j]=1;

for(i=head[j];i!=-1;i=bian[i].next)

if(dis[bian[i].v]>dis[j]+bian[i].w) {

dis[bian[i].v]=dis[j]+bian[i].w;

q.push(make_pair(dis[bian[i].v],bian[i].v));

}

}

if(dis[end]<inf)

return dis[end];

return -1;

}

int main() {

int i,j,a,b;

while(scanf("%d%d",&n,&m)!=EOF) {

yong=0;

memset(head,-1,sizeof(head));

while(m--) {

scanf("%d%d%d",&a,&b,&j);

Dcreat(a,b,j);

}

scanf("%d%d",&a,&b);

printf("%d\n",dijkstra(a,b));

}

return 0;

}

//定义结构体优先队列

#include<stdio.h>

#include<queue>

#include<iostream>

#include<vector>

using namespace std;

#define N 2100

#define inf 1000000000

int n,m;

struct node {

int u,v,w,next;

}bian
;

int yong,head
;

void creat(int u,int v,int w) {

bian[yong].u=u;

bian[yong].v=v;

bian[yong].w=w;

bian[yong].next=head[u];

head[u]=yong++;

}

void Dcreat(int u,int v,int w) {

creat(u,v,w);

creat(v,u,w);

}

struct nodee {

int len,v;

friend bool operator<(nodee a,nodee b) {

if(a.len!=b.len)

return a.len>b.len;

return a.v>b.v;

}

};

int dijkstra(int u,int end) {

int dis
,i,j,visit
;

memset(visit,0,sizeof(visit));

for(i=0;i<n;i++)

dis[i]=inf;

dis[u]=0;

//typedef pair<int ,int >p;

//priority_queue<p,vector<p>,greater<p> >q;

// q.push(make_pair(dis[u],u));

priority_queue<nodee>q;

nodee cur,now;

cur.len=0;

cur.v=u;

q.push(cur);

while(!q.empty()) {

nodee cur=q.top();

// j=cur.second;

q.pop();

if(visit[cur.v])continue;

visit[cur.v]=1;

for(i=head[cur.v];i!=-1;i=bian[i].next)

if(dis[bian[i].v]>dis[cur.v]+bian[i].w) {

dis[bian[i].v]=dis[cur.v]+bian[i].w;

now.len=dis[bian[i].v];

now.v=bian[i].v;

q.push(now);

}

}

if(dis[end]<inf)

return dis[end];

return -1;

}

int main() {

int i,j,a,b;

while(scanf("%d%d",&n,&m)!=EOF) {

yong=0;

memset(head,-1,sizeof(head));

while(m--) {

scanf("%d%d%d",&a,&b,&j);

Dcreat(a,b,j);

}

scanf("%d%d",&a,&b);

printf("%d\n",dijkstra(a,b));

}

return 0;

}