【POJ 1125】Stockbroker Grapevine

【POJ 1125】Stockbroker Grapevine

最短路 不过这题数据很水。。主要想大牛们试试南阳OJ同题 链接如下:

http://acm.nyist.net/JudgeOnline/talking.php?pid=426&page=2

数据增大很多 用到很多东西才能过 (弱没过，，，

这题就是求最短路寻找所有通路中最大权的最小值外加考验英语水平……

Floyd 208K 0MS 1162B

#include

using namespace std;

int dis[111][111],n;

void Floyd()
{
    int i,j,k,tmax,mmax,f;

    for(k = 1; k <= n; ++k)
        for(i = 1; i <= n; ++i)
            for(j = 1; j <= n; ++j)
                if(dis[i][j] > dis[i][k] + dis[k][j])
                    dis[i][j] = dis[i][k] + dis[k][j];
    mmax = INF;

    for(i = 1; i <= n; ++i)
    {
        f = 1;
        tmax = 0;
        for(j = 1; j <= n; ++j)
        {
            if(i == j) continue;
            if(dis[i][j] == INF) f = 0;
            tmax = max(tmax,dis[i][j]);
        }
        if(f && tmax < mmax)
        {
            k = i;
            mmax = tmax;
        }
    }
    if(mmax != INF) printf("%d %d\n",k,mmax);
    else puts("disjoint");
}

int main()
{
    int i,k,v;
    while(~scanf("%d",&n) && n)
    {
        memset(dis,INF,sizeof(dis));
        for(i = 1; i <= n; ++i)
        {
            scanf("%d",&k);
            while(k--)
            {
                scanf("%d",&v);
                scanf("%d",&dis[i][v]);
            }
        }
        Floyd();
    }

    return 0;
}

Dijkstra 168K 0MS 1491B

#include

using namespace std;

typedef struct Edge
{
    int v,w,next;
}Edge;

Edge eg[11111];
int head[111],dis[111],n,tp;
bool vis[111];

int Dijkstra(int u)
{
    memset(dis,INF,sizeof(dis));
    memset(vis,0,sizeof(vis));
    dis[u] = 0;

    int m,p,i,j;

    for(i = 1; i <= n; ++i)
    {
        p = -1;
        m = INF;
        for(j = 1; j <= n; ++j)
        {
            if(!vis[j] && dis[j] < m)
            {
                p = j;
                m = dis[j];
            }
        }
        if(i == n || p == -1) break;
        vis[p] = 1;

        for(j = head[p]; j != -1; j = eg[j].next)
        {
            if(!vis[eg[j].v] && dis[eg[j].v] > dis[p] + eg[j].w)
                dis[eg[j].v] = dis[p] + eg[j].w;
        }

    }
    if(p == -1) return INF;
    return dis[p];
}

int main()
{
    int i,k,m,t;
    while(~scanf("%d",&n) && n)
    {
        m = INF;
        tp = 0;
        memset(head,-1,sizeof(head));
        for(i = 1; i <= n; ++i)
        {
            scanf("%d",&k);
            while(k--)
            {
                scanf("%d %d",&eg[tp].v,&eg[tp].w);
                eg[tp].next = head[i];
                head[i] = tp++;
            }
        }
        k = 0;
        for(i = 1; i <= n; ++i)
        {
            t = Dijkstra(i);
            if(t < m)
            {
                k = i;
                m = t;
            }
        }
        if(k)
            printf("%d %d\n",k,m);
        else puts("disjoint");
    }

    return 0;
}

SPFA 180K 0MS 1668B

#include

using namespace std;

typedef struct Edge
{
    int v,w,next;
}Edge;

Edge eg[11111];
int head[111],dis[111],n,tp;
bool vis[111];

int SPFA(int u)
{
    memset(dis,INF,sizeof(dis));
    memset(vis,0,sizeof(vis));
    dis[u] = 0;
    queue <int> q;
    q.push(u);
    int v,w,i,p,m;

    while(!q.empty())
    {
        p = q.front();
        q.pop();
        vis[u] = 0;
        for(i = head[p]; i != -1; i = eg[i].next)
        {
            v = eg[i].v;
            w = eg[i].w;
            if(dis[v] > dis[p] + w)
            {
                dis[v] = dis[p] + w;
                if(!vis[v])
                {
                    vis[v] = 1;
                    q.push(v);
                }
            }
        }
    }
    m = 0;
    for(i = 1; i <= n; ++i)
    {
        if(i == u) continue;
        if(dis[i] == INF) return INF;
        m = max(m,dis[i]);
    }
    return m;
}

int main()
{
    int i,k,m,t;
    while(~scanf("%d",&n) && n)
    {
        m = INF;
        tp = 0;
        memset(head,-1,sizeof(head));
        for(i = 1; i <= n; ++i)
        {
            scanf("%d",&k);
            while(k--)
            {
                scanf("%d %d",&eg[tp].v,&eg[tp].w);
                eg[tp].next = head[i];
                head[i] = tp++;
            }
        }
        k = 0;
        for(i = 1; i <= n; ++i)
        {
            t = SPFA(i);
            if(t < m)
            {
                k = i;
                m = t;
            }
        }
        if(k)
            printf("%d %d\n",k,m);
        else puts("disjoint");
    }

    return 0;
}

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