Frogger POJ 2253

#include<stdio.h>
#include<string.h>
#include<math.h>
#include<algorithm>
#include<queue>
using namespace std;
typedef long long LL;
#define oo 0x3f3f3f3f
#define maxn 500
double maps[maxn][maxn], dist[maxn];
int v[maxn];
int n;

struct node
{
    int x, y;
}A[maxn];

double F(int i, int j)
{
    return (sqrt(pow((double)A[i].x-A[j].x, 2)+pow((double)A[i].y-A[j].y, 2)));
}

double Dij()
{
    memset(v, 0, sizeof(v));
    for(int i=1; i<=n; i++)
    dist[i] = maps[1][i];

    dist[1] = 0;
    v[1] = 1;

    for(int i=1; i<n; i++)
    {
        int index;
        double mins = 10000000;
        for(int j=1; j<=n; j++)
        {
            if(!v[j] && dist[j] < mins)
            {
                index = j;
                mins = dist[j];
            }
        }

        v[index] = 1;

        for(int j=1; j<=n; j++)
        {
            if(!v[j])
            {
                double maxs = max(mins, maps[index][j]);
                 if(dist[j]>maxs) dist[j] = maxs;
            }
        }
    }
    return dist[2];
}

int main()
{
     int cnt = 1;
     while(scanf("%d", &n), n)
     {
         for(int i=1; i<=n; i++)
            scanf("%d %d", &A[i].x, &A[i].y);

        for(int i=1; i<=n; i++)
        {
            for(int j=1; j<i; j++)
            {
                maps[i][j] = maps[j][i] = F(i, j);
            }
            maps[i][i] = 0;
        }

       double ans = Dij();
       printf("Scenario #%d\n", cnt++);
       printf("Frog Distance = %.3f\n\n", ans);

     }
    return 0;
}

#include<algorithm>
#include<queue>
#include<stdio.h>
#include<string.h>
#include<vector>
#include<math.h>
using namespace std;

const int maxn = 205;
const int oo = 0xfffffff;

struct point
{
    double x, y;
} p[maxn];
struct node
{
    int y;
    double len;
    node(int y, double len):y(y), len(len) {}
};
vector<node> G[maxn];
double v[maxn];

//求两点间的距离
double Len(point a, point b)
{
    return sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y));
}
void Spfa()
{
    queue<int> Q;
    Q.push(1);

    while(Q.size())
    {
        int s = Q.front();
        Q.pop();
        int len = G[s].size();

        for(int i=0; i<len; i++)
        {
            node q = G[s][i];

            if(v[s] < v[q.y] && q.len < v[q.y])
            {
                v[q.y] = max(v[s], q.len);//要选取一条路上的最大的那条边
                Q.push(q.y);
            }
        }
    }
}

int main()
{
    int N, t=1;

    while(scanf("%d", &N), N)
    {
        int i, j;

        for(i=1; i<=N; i++)
            scanf("%lf%lf", &p[i].x, &p[i].y);

        for(i=1; i<=N; i++)
            for(j=1; j<=N; j++)
            {
                if(i == j)
                    continue;

                double len = Len(p[i], p[j]);
                G[i].push_back(node(j, len));
            }

        for(i=1; i<=N; i++)
            v[i] = oo;
        v[1] = 0;

        Spfa();

        if(t != 1)printf("\n");
        printf("Scenario #%d\n", t++);
        printf("Frog Distance = %.3f\n", v[2]);

        for(i=1; i<=N; i++)
            G[i].clear();
    }

    return 0;