POJ 1269

中学的 又用上了。

#include <iostream>
#include <cstring>
#include <cstdio>

using namespace std;

int x1,y1,x2,y2,x3,y3,x4,y4;
double k1,k2,k3,d1,d2;
double x,y;

bool asure(){
    if(x1==x2||x3==x4){
        if(x1==x2&&x3==x4&&x1==x3)
        printf("LINE
");
        else if(x1==x2&&x3==x4&&x1!=x3)
        printf("NONE
");
        else{
            if(x1==x2){
                k2=(y3-y4)*1.0/(x3-x4)*1.0;
                d2=y3*1.0-k2*x3;
                x=x1;
                y=k2*x+d2;
            }
            else {
                k1=(y1-y2)*1.0/(x1-x2)*1.0;
                d1=y1*1.0-k1*x1;
                x=x3;
                y=k1*x+d1;
            }
            printf("POINT %0.2lf %0.2lf
",x,y);
        }
        return true;
    }
    return false;
}


int main(){
    int T;
    while(scanf("%d",&T)!=EOF){
        printf("INTERSECTING LINES OUTPUT
");
        while(T--){
            scanf("%d%d%d%d%d%d%d%d",&x1,&y1,&x2,&y2,&x3,&y3,&x4,&y4);
            if(asure()) continue;
            k1=(y1-y2)*1.0/(x1-x2)*1.0; k2=(y3-y4)*1.0/(x3-x4)*1.0;
            if(k1==k2){
                k3=(y2-y3)*1.0/(x2-x3)*1.0;
                if(k1==k3){
                    printf("LINE
");
                }
                else printf("NONE
");
                continue;
            }
            else {
                d1=y1*1.0-k1*x1;
                d2=y3*1.0-k2*x3;
                y=(k2*d1-k1*d2)/(k2-k1);
                x=(y-d1)*1.0/k1;
                printf("POINT %0.2lf %0.2lf
",x,y);
            }
        }
        printf("END OF OUTPUT
");
    }
    return 0;
}