各种最短路模板

来源：互联网发布：linux下find命令详解编辑：程序博客网时间：2024/06/17 02:04

原创 http://blog.csdn.net/shuangde800 ， By D_Double (转载请标明)

原创大佬的代码格式不是我喜欢的风格...所以都被我稍作修改了下...

1. Dijkstra 普通版

#include<stdio.h>#include<string.h>const int N=105, INF=9999999;int d[N], w[N][N],vis[N],n,m;void Dijkstra(int src){int i,j,u,tmp;    for(i=1;i<=n;i++)    d[i]=INF;    d[src]=0;     memset(vis, 0, sizeof(vis));    for(i=1;i<=n;i++){        u=-1;        for(j=1;j<=n;j++)        {        if(!vis[j]){            if(u==-1||d[j]<d[u]) u=j;        }        }        vis[u]=1;        for(j=1;j<=n;j++)        {        if(!vis[j]){            tmp=d[u]+w[u][j];            if(tmp<d[j]) d[j] = tmp;        }        }    }}int main(){    int a,b,c,i,j;    while(scanf("%d%d",&n,&m)){if(n==0&&m==0)break;        for(i=1;i<=n;i++){            w[i][i]=INF;            for(j=i+1;j<=n;j++)            w[i][j]=w[j][i]=INF;        }        for(i=0;i<m;i++){            scanf("%d%d%d",&a,&b,&c);            w[a][b]=w[b][a]=c;        }        Dijkstra(1);        printf("%d\n",d[n]);    }    return 0;}

2. Dijkstra+邻接表(用数组实现)+优先队列优化

#include<cstdio>#include<cstring>#include<utility>#include<queue>using namespace std;const int N=20005;const int INF=9999999;typedef pair<int,int>pii;priority_queue<pii, vector<pii>, greater<pii> >q;int d[N], first[N], u[N], v[N], w[N], next[N],n,m;bool vis[N];// 无向图的输入，注意每输入的一条边要看作是两条边void read_graph(){    memset(first,-1,sizeof(first)); //初始化表头    for(int e=1;e<=m;e++){        scanf("%d%d%d",&u[e],&v[e],&w[e]);        u[e+m]=v[e];v[e+m]=u[e]; w[e+m]=w[e];  // 增加一条它的反向边               next[e]=first[u[e]];  // 插入链表        first[u[e]]=e;        next[e+m]=first[u[e+m]]; // 反向边插入链表        first[u[e+m]]=e+m;    }}void Dijkstra(int src){    memset(vis,0,sizeof(vis));    for(int i=1;i<=n;i++) d[i]=INF;    d[src]=0;    q.push(make_pair(d[src],src));    while(!q.empty()){        pii u=q.top(); q.pop();        int x = u.second;        if(vis[x]) continue;        vis[x]=true;        for(int e=first[x];e!=-1;e=next[e])        {        if(d[v[e]]>d[x]+w[e]){            d[v[e]]=d[x]+w[e];            q.push(make_pair(d[v[e]],v[e]));        }         }    }}int main(){    int a,b,c;    while(scanf("%d%d",&n,&m)){if(n==0&&m==0)break;        read_graph();        Dijkstra(1);        printf("%d\n",d[n]);    }    return 0;}

3. Dijkstra+邻接表(用vecor实现)+优先队列优化

#include<cstdio>#include<cstring>#include<utility>#include<queue>#include<vector>using namespace std;const int N=105;const int INF=9999999;typedef pair<int,int>pii;vector<pii>G[N];priority_queue<pii, vector<pii>, greater<pii> >q;int d[N], first[N], u[N], v[N], w[N], next[N],n,m;bool vis[N];// 无向图的输入，注意没输入的一条边要看作是两条边void read_graph(){int a,b,c,i;    for(i=1; i<=n;i++)    G[i].clear();       for(i=1; i<=m;i++){        scanf("%d%d%d",&a,&b,&c);        G[a].push_back(make_pair(b,c));        G[b].push_back(make_pair(a,c));    }}void Dijkstra(int src){    memset(vis,0,sizeof(vis));    for(int i=1;i<=n;i++) d[i]=INF;    d[src]=0;    q.push(make_pair(d[src], src));    while(!q.empty()){        pii t=q.top(); q.pop();        int u=t.second;        if(vis[u]) continue;        vis[u]=true;        for(int v=0;v<G[u].size();v++)        {       if(d[G[u][v].first] > d[u]+G[u][v].second){            d[G[u][v].first] = d[u]+G[u][v].second;            q.push(make_pair(d[G[u][v].first],G[u][v].first));        }        }    }}int main(){    int a,b,c;    while(scanf("%d%d",&n,&m)){if(n==0&&m==0)break;        read_graph();        Dijkstra(1);        printf("%d\n", d[n]);    }    return 0;}

4.Bellman-Ford算法

#include<cstdio>#include<cstring>#include<utility>#include<queue>using namespace std;const int N=20005;const int INF=9999999;int n, m, u[N],v[N],w[N], d[N];// 无向图的输入，注意每输入的一条边要看作是两条边inline void read_graph(){    for(int e=1;e<=m;e++)    scanf("%d%d%d",&u[e],&v[e],&w[e]);}inline void Bellman_Ford(int src){    for(int i=1;i<=n;i++) d[i]=INF;    d[src]=0;    for(int k=0;k<n-1;k++){        for(int i=1;i<=m;i++){             int x=u[i],y=v[i];            if(d[x]<INF){                if(d[y]>d[x]+w[i])                d[y]=d[x]+w[i];            }            if(d[y]<INF){                if(d[x]>d[y]+w[i])                d[x]=d[y]+w[i];            }        }    }}int main(){    int a,b,c;    while(scanf("%d%d",&n,&m)){if(n==0&&m==0)break;        read_graph();        Bellman_Ford(1);        printf("%d\n", d[n]);    }    return 0;}

5.SPFA

#include<cstdio>#include<cstring>#include<utility>#include<queue>using namespace std;const int N=20005;const int INF=2147483646>>1;int n, m, first[N],next[N],u[N],v[N],w[N], d[N];bool vis[N];queue<int>q;inline void read_graph(){    memset(first, -1, sizeof(first));    for(int e=1;e<=m;e++){        scanf("%d%d%d",&u[e],&v[e],&w[e]);        u[e+m]=v[e],v[e+m]=u[e],w[e+m]=w[e];        next[e]=first[u[e]];        first[u[e]]=e;        next[e+m]=first[u[e+m]];        first[u[e+m]]=e+m;    }}void SPFA(int src){    memset(vis,0,sizeof(vis));    for(int i=1;i<=n;i++)d[i]=INF;    d[src]=0;    vis[src]=true;    q.push(src);    while(!q.empty()){        int x = q.front();  q.pop();        vis[x] = false;        for(int e=first[x]; e!=-1; e=next[e]){            if(d[x]+w[e] < d[v[e]]){                d[v[e]] = d[x]+w[e];                if(!vis[v[e]]){                    vis[v[e]] = true;                    q.push(v[e]);                }            }        }    } }int main(){    int a,b,c;    while(scanf("%d%d",&n,&m)){if(n==0&&m==0)break;        read_graph();        SPFA(1);        printf("%d\n", d[n]);    }    return 0;}

6.Floyd算法

#include<cstdio>#include<cstring>#include<utility>#include<queue>using namespace std;const int N=105;const int INF=2147483646;int n, m, d[N][N];inline void read_graph(){    for(int i=1;i<=n;i++){        d[i][i]=INF;        for(int j=i+1;j<=n;j++)        d[i][j]=d[j][i]=INF;    }    int a,b,c;    for(int e=1;e<=m;e++){        scanf("%d%d%d",&a,&b,&c);        d[a][b]=d[b][a]=c;    }}inline void Floyd(int src){    for(int k=1;k<=n;k++){        for(int i=1;i<=n;i++){            for(int j=1;j<=n;j++)            {            if(d[i][k]<INF&&d[k][j]<INF)             d[i][j]=min(d[i][j], d[i][k]+d[k][j]);            }                        }    }}int main(){    int a,b,c;    while(scanf("%d%d",&n,&m)){if(n==0&&m==0)break;        read_graph();        Floyd(1);        printf("%d\n", d[1][n]);    }    return 0;}

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