hdu1245 Saving James Bond ，卡精度

最短路问题，数据小，各种算法都可以，我用dijkstra和floyd两种算法都提交成功了。

可以将不多于一百只鳄鱼转化为点，小岛做起点，岸边作终点，注意小岛告诉我们直径，应该考虑进去。

这题据说很卡精度，我wa了许多次才过的。写的时候比较晕，结果出了一堆问题，居然把step变量类型定义错误。。。

不过，纠结的是，这道题我用GCC和G++提交都不行，用C++和C就ac了，比较无语。

dijkstra：

#include<stdio.h>#include<stdlib.h>#include<string.h>#include<math.h>#define INF 200000000double x[102],y[102],map[102][102],dis[102];int visit[102],n,step[102];void dij(){    int i,j,k,min,v;    memset(visit,0,sizeof(visit));    for(i=1;i<=n;i++)    {        for(j=1,min=INF,v=0;j<=n;j++)        {            if(visit[j]!=1&&dis[j]<min)            {                min=dis[j];                v=j;            }        }        visit[v]=1;        for(j=1;j<=n+1;j++)        {            if(dis[v]+map[v][j]<dis[j])            {                dis[j]=dis[v]+map[v][j];                step[j]=step[v]+1;            }            else if(dis[v]+map[v][j]==dis[j])            {                if(step[j]>step[v]+1)                    step[j]=step[v]+1;            }        }    }    if(dis[n+1]!=INF)        printf("%.2lf %d\n",dis[n+1],step[n+1]);    else        printf("can't be saved\n");}double mm(double a,double b){    return a>b?b:a;}int main(){    int i,j,k,l;    double d;    while(scanf("%d%lf",&n,&d)!=EOF)    {        for(i=0;i<=n+1;i++)            dis[i]=INF;        for(i=0;i<=n+1;i++)            for(j=0;j<=n+1;j++)                map[i][j]=INF;        for(i=1;i<=n;i++)            scanf("%lf%lf",&x[i],&y[i]);        for(i=1;i<=n;i++)        {            for(j=1;j<=n;j++)            {                if(sqrt(fabs(x[i]-x[j])*fabs(x[i]-x[j])+fabs(y[i]-y[j])*fabs(y[i]-y[j]))<=d)                {                    map[i][j]=sqrt(fabs(x[i]-x[j])*fabs(x[i]-x[j])+fabs(y[i]-y[j])*fabs(y[i]-y[j]));                    map[j][i]=sqrt(fabs(x[i]-x[j])*fabs(x[i]-x[j])+fabs(y[i]-y[j])*fabs(y[i]-y[j]));                }            }            if(sqrt(fabs(x[i])*fabs(x[i])+fabs(y[i])*fabs(y[i]))-7.5<=d)            {                if(sqrt(fabs(x[i]-0)*fabs(x[i]-0)+fabs(y[i]-0)*fabs(y[i]-0))-7.5>0)                {                    dis[i]=sqrt(fabs(x[i]-0)*fabs(x[i]-0)+fabs(y[i]-0)*fabs(y[i]-0))-7.5;                    step[i]=1;                }            }            if(fabs(fabs(x[i])-50)<=d||fabs(fabs(y[i])-50)<=d)                map[i][n+1]=mm(fabs(fabs(x[i])-50),fabs(fabs(y[i])-50));            else                map[i][n+1]=INF;        }        dij();        /*for(i=1;i<=n+1;i++)        {            for(j=1;j<=n+1;j++)                printf("%lf ",map[i][j]);            printf("\n");        }        for(i=1;i<=n+1;i++)            printf("%lf ",dis[i]);        printf("\n");*/    }    return 0;}

floyd：

#include<stdio.h>#include<stdlib.h>#include<string.h>#include<math.h>#define INF 200000000double x[102],y[102],map[102][102];int n,step[102][102];double mm(double a,double b){    return a>b?b:a;}int main(){    int i,j,k,l;    double d;    while(scanf("%d%lf",&n,&d)!=EOF)    {        for(i=0;i<=n+1;i++)            for(j=0;j<=n+1;j++)                map[i][j]=INF;        for(i=0;i<=n+1;i++)            map[i][i]=0;        for(i=0;i<=n+1;i++)            for(j=0;j<=n+1;j++)            {                if(i==j)                    step[i][j]=0;                else                    step[i][j]=1;            }        /*for(i=0;i<=n+1;i++)        {            for(j=0;j<=n+1;j++)                printf("%.2lf ",map[i][j]);            printf("\n");        }        for(i=0;i<=n+1;i++)        {            for(j=0;j<=n+1;j++)                printf("%d ",step[i][j]);            printf("\n");        }*/        for(i=1;i<=n;i++)            scanf("%lf%lf",&x[i],&y[i]);        for(i=1;i<=n;i++)        {            for(j=1;j<=n;j++)            {                if(sqrt(fabs(x[i]-x[j])*fabs(x[i]-x[j])+fabs(y[i]-y[j])*fabs(y[i]-y[j]))<=d)                {                    map[i][j]=sqrt(fabs(x[i]-x[j])*fabs(x[i]-x[j])+fabs(y[i]-y[j])*fabs(y[i]-y[j]));                    map[j][i]=sqrt(fabs(x[i]-x[j])*fabs(x[i]-x[j])+fabs(y[i]-y[j])*fabs(y[i]-y[j]));                }            }            if(sqrt(fabs(x[i])*fabs(x[i])+fabs(y[i])*fabs(y[i]))-7.5<=d)            {                if(sqrt(fabs(x[i]-0)*fabs(x[i]-0)+fabs(y[i]-0)*fabs(y[i]-0))-7.5>0)                {                    map[0][i]=sqrt(fabs(x[i]-0)*fabs(x[i]-0)+fabs(y[i]-0)*fabs(y[i]-0))-7.5;                }            }            if(fabs(fabs(x[i])-50)<=d||fabs(fabs(y[i])-50)<=d)                map[i][n+1]=mm(fabs(fabs(x[i])-50),fabs(fabs(y[i])-50));        }        for(k=0;k<=n+1;k++)            for(i=0;i<=n+1;i++)                for(j=0;j<=n+1;j++)        {            if(map[i][k]+map[k][j]<map[i][j])            {                map[i][j]=map[i][k]+map[k][j];                step[i][j]=step[i][k]+step[k][j];            }            else if(map[i][k]+map[k][j]==map[i][j])            {                if(step[i][j]>step[i][k]+step[k][j])                    step[i][j]=step[i][k]+step[k][j];            }        }        if(map[0][n+1]==INF)            printf("can't be saved\n");        else            printf("%.2lf %d\n",map[0][n+1],step[0][n+1]);    }    return 0;}