• 最短路算法 Dijkstra算法 HDU 2066 一个人的旅行


    原题:http://acm.hdu.edu.cn/showproblem.php?pid=2066

    本人写的 至今还不知道为什么 WA 0rz!

    //HDU 2066
    #include <iostream>
    using namespace std;
    const int MAX = 1002;
    const int INF = 0x7FFFFFF;//4字节int最大值
    int g[MAX+1][MAX+1];//存储图
    int hash[MAX+1];//存储是否访问
    int path[MAX+1];//存储从源到i的最短路径,及特殊路径
    int T , S , D , L;
    int s[MAX];
    int d[MAX];

    #define min(a,b) a>b?b:a

    #define max(a,b) a>b?a:b

    int Dijkstra ( int beg , int end ) //Dijkstra算法,求beg到end的最短路径长
    {
        path[beg] = 0;
        hash[beg] = false;//源点访问
        while ( beg != end )
        {
       int m = INF, temp;
       for ( int i = 0; i <= L+1; ++ i )
       {
        if ( g[beg][i] != INF )
         path[i] = min ( path[i], path[beg] + g[beg][i] );
        if ( m > path[i] && hash[i] )
        {
         m = path[i];
         temp = i;
        }          
       }
       beg = temp;
       if ( m == INF )
        break;
       hash[beg] = false;
        }
        if ( path[end] == INF )
       return -1;
        return path[end];
    }

    int main()
    {
    int i , a , b , time ;

    while(cin>>T>>S>>D)
    {
       L = 0;
       for (i = 0; i != MAX; ++ i )
       {
        hash[i] = true;
        path[i] = INF;
        for ( int j = 0; j < MAX; ++ j )
        {
         g[i][j] = INF;
        }
       }
      
       for(i=0; i<T; i++)
       {
        cin>>a>>b>>time;
       if(time < g[a][b])
         g[a][b] = g[b][a] = time;
        if(L < max(a,b))
         L = max(a,b);
       }
      
       for(i=1 ; i<=S; i++)
       {
        cin>>s[i];
        g[0][s[i]] = g[s[i]][0] = 0;
       }
      
       for(i=1 ; i<=D; i++)
       {
        cin>>d[i];
       g[d[i]][L+1] = g[L+1][d[i]] = 0;
       }
      cout<<Dijkstra(0,L)<<endl;
    }
    return 0;
    }

    一个思路 AC的代码:

    #include <iostream>
    using namespace std;
    const int INF = 0x7FFFFFFF;
    int T,S,D,L;
    const int MAXN=1005; //点个数
    int graph[MAXN][MAXN];
    int s[MAXN];
    int d[MAXN];
    int Dijkstra ( int beg, int end )
    {
    bool hash[MAXN];
    int path[MAXN];
    for ( int i = 0; i <= L; ++ i )
    {
    hash[i] = true;
    path[i] = INF;
    }
    hash[beg] = false;
    path[beg] = 0;
    while ( beg != end )
    {
    for ( int i = 0; i <= L; ++ i )
    {
    if ( graph[beg][i] != 0 )
    {
    if ( path[i] > path[beg] + graph[beg][i] )
    path[i] = path[beg] + graph[beg][i];
    }
    }
    int min = INF;
    for ( int i = 0; i <= L; ++ i )
    {
    if ( min > path[i] && hash[i] )
    {
    min = path[i];
    beg = i;
    }
    }
    hash[beg] = false;
    }
    return path[end];
    }

    int main ()
    {
    while ( scanf ( "%d%d%d",&T,&S,&D ) != EOF )
    {
    memset ( graph , 0 , sizeof ( graph ) );
    L = 0;
    for ( int i = 1; i <= T; ++ i )
    {
    int r,c,cost;
    scanf ( "%d%d%d",&r,&c,&cost );
    if ( graph[r][c] == 0 )
    graph[r][c] = graph[c][r] = cost ;
    else
    {
    if ( cost < graph[r][c] )
    graph[r][c] = graph[c][r] = cost ;
    }
    if ( L < max ( r,c ) )
    L = max ( r,c );
    }
    for ( int i = 0; i != S; ++ i )
    {
    scanf ( "%d",&s[i] );
    graph[0][ s[i] ] = 1;
    graph[ s[i] ][0] = 1;
    }
    L ++;
    for ( int i = 0; i != D; ++ i )
    {
    scanf ( "%d",&d[i] );
    graph[ d[i] ][ L ] = 1;
    graph[ L ][ d[i] ] = 1;
    }

    cout << Dijkstra ( 0,L ) - 2 << endl;
    }
    return 0;
    }



    NB 大神 的邻接表 0ms 代码:

    #include <iostream>
    #define MAX 1005
    #define INF 0x7FFF
    #define CMP(A,B) (A.d < B.d)
    using namespace std;
    int d[MAX][MAX];
    class HNode {
    public:
    int v;
    int d;
    };
    class Heap {
    public:
    HNode h[MAX * 2];
    int n, p, c;
    Heap() {
    n = 0;
    }
    void inline ins(HNode e) {
    for (p = ++n; p > 1 && CMP(e,h[p>>1]); h[p] = h[p>>1], p >>= 1)
    ;
    h[p] = e;
    }
    int inline pop(HNode &e) {
    if (!n)
    return 0;
    for (e = h[p = 1], c = 2; c < n
    && CMP(h[c += (CMP(h[c + 1],h[c]) && c < n - 1)], h[n]);
    h[p] = h[c], p = c, c <<= 1)
    ;
    h[p] = h[n--];
    return 1;
    }
    };
    int Dijkstra(int A, int B, int N) {
    int dist[MAX];
    int mask[MAX];
    int Tmp;
    Heap h;
    HNode e, ne;

    for (int i = 0; i < N; i++) {
    dist[i] = INF;
    mask[i] = 0;
    }
    dist[e.v = A] = (e.d = 0);
    h.ins(e);
    while (h.pop(e)) {
    if (!mask[e.v]) {
    mask[e.v] = 1;
    for (int i = 0; i < N; i++) {
    if (!mask[i] && (Tmp = e.d + d[e.v][i])
    < dist[i]) {
    dist[ne.v = i] = (ne.d = Tmp);
    h.ins(ne);
    }
    }
    }
    }
    return dist[B];
    }
    int main() {
    int T, S, D, M;
    int st, en, tm;
    while (scanf("%d %d %d", &T, &S, &D)!=EOF) {
    M = 0;
    for (int i = 0; i < MAX; i++)
    for (int j = 0; j < MAX; j++)
    d[i][j] = INF;
    for (int i = 0; i < T; i++) {
    scanf("%d %d %d", &st, &en, &tm);
    if (tm < d[st][en]) {
    d[st][en] = d[en][st] = tm;
    }

    M = st> M ? st : M;
    M = en> M ? en : M;
    }
    M = M + 1;
    for (int i = 0; i < S; i++) {
    scanf("%d", &st);
    d[0][st] = 1;
    d[st][0] = 1;
    }

    for (int i = 0; i < D; i++) {
    scanf("%d", &en);
    d[M][en] = 1;
    d[en][M] = 1;
    }
    cout<<Dijkstra(0, M, M+1)-2<<endl;
    }
    return 0;
    }



    作者:BuildNewApp
    出处:http://syxchina.cnblogs.comBuildNewApp.com
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  • 原文地址:https://www.cnblogs.com/syxchina/p/2197366.html
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