poj2253

dijkstra

把存最短距离的数组改为存储frog distance即可

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
using namespace std;

const int maxn = 201, inf = 1000000000;

struct point
{
	int x, y;
} stone[maxn];

int n;
double dist[maxn];
bool vis[maxn];

void init()
{
	for (int i = 0; i < n; i++)
		scanf("%d%d", &stone[i].x, &stone[i].y);
}

double distan(point &a, point &b)
{
	return sqrt((a.x - b.x) * (a.x - b.x) + (a.y - b.y) * (a.y - b.y));
}

void dijkstra()
{
	double best = 0;
	int besti = 0;

	for (int i = 0; i < n; i++)
		dist[i] = inf;
	memset(vis, 0, sizeof(vis));
	vis[0] = true;
	dist[0] = 0;
	while (besti != -1 && !vis[1])
	{
		for (int i = 0; i < n; i++)
		{
			double temp = max(dist[besti], distan(stone[i], stone[besti]));
			if (dist[i] > temp)
				dist[i] = temp;
		}
		best = inf;
		besti = -1;
		for (int i = 0; i < n; i++)
			if (!vis[i] && dist[i] < best)
			{
				best = dist[i];
				besti = i;
			}
		vis[besti] = true;
	}
}

int main()
{
	//freopen("D:\\t.txt", "r", stdin);
	int t = 0;
	while (scanf("%d", &n) != EOF && n != 0)
	{
		init();
		dijkstra();
		t++;
		printf("Scenario #%d\nFrog Distance = %.3f\n\n", t, dist[1]);
	}
	return 0;
}