POJ1328雷达装置

//POJ1328
//Radar 
//http://poj.org/problem?id=1328
#include
#include
#define SIZE 100

double arr[SIZE][2];

typedef struct intersection{
    double LP;
    double RP;
}Inter;

Inter data[SIZE];

//将岛屿按照坐标X排序(升序 
void Change(int num){
    int r1,r2;
    double tempx,tempy;
    for(r1=0;r1){
        for(r2=r1+1;r2){
            if(arr[r1][0]>arr[r2][0]){
                tempx=arr[r1][0];
                arr[r1][0]=arr[r2][0];
                arr[r2][0]=tempx;
                
                tempy=arr[r1][1];
                arr[r1][1]=arr[r2][1];
                arr[r2][1]=tempy;
            }
        }
    }
}

//计算以(x,y)为圆心，雷达距离为半径所画的圆，与X轴的交点 
void Cal(double x, double y, int radar, int p){
    double temp=sqrt(pow(radar*1.0,2.0)-pow(y,2.0));
    data[p].LP=x-temp;
    data[p].RP=x+temp;
}

//num是岛屿数，radar是雷达的覆盖范围 
int Check(int num, int radar){
    int RadarCount=0,
        r1=0;
    
    for(r1=0;r1){
        Cal(arr[r1][0],arr[r1][1],radar,r1);
    }
    
    int r2;
    for(r1=0;r1<num;){
        RadarCount++;
        //printf("%d\n",temp);
        for(r2=r1+1;r2){
            //printf("r1:%d,r2:%d\n",r1,r2);
            if(data[r1].RP>data[r2].LP);
            else break;
        }
        r1=r2;
    }
    
    /*
    检查计算岛屿与X轴交点的坐标是否正确 
    for(r1=0;r1*/
    
    return RadarCount;
}

int main(void){
    //n是岛屿数，d是雷达的覆盖距离 
    int n,d,r1,r2;
    int result[SIZE],resultcount=0,nothing=0;
    
    while(scanf("%d%d",&n,&d)==2 && n!=0 && d!=0){
        nothing=0;
        for(r1=0;r1){
            scanf("%lf%lf", &arr[r1][0], &arr[r1][1]);
            if(arr[r1][1]>d){
                result[resultcount]=-1;
                nothing=-1;
            }
        }
        //puts("Get!");
        if(nothing!=0) continue;
        
        //for(r1=0;r1//将岛屿按找X坐标排序
        Change(n); 
        //for(r1=0;r1
        result[resultcount]=Check(n,d);
        resultcount++;
    }
    
    for(r1=0;r1"case%d:%d\n",r1+1,result[r1]);
    
    return 0;
}