OJ-Problems-Source/HDOJ/1687_autoAC.cpp

#include <stdio.h>
#include <algorithm>
using std::sort;
using std::swap;
double X, Y;
struct Node{
    double left, right;
} arr[102];
double getX(double a, double b){
    return X - Y * (X - a) / (Y - b);
}
bool cmp(Node a, Node b){
    return a.left < b.left;
}
int main(){
    double x1, y1, x2, y2, flag;
    int t, n, ans;
    scanf("%d", &t);
    while(t--){
        scanf("%d", &n);
        scanf("%lf%lf", &X, &Y);
        for(int i = 0; i < n; ++i){
            scanf("%lf%lf%lf%lf", &x1, &y1, &x2, &y2);
            arr[i].left = getX(x1, y1);
            arr[i].right = getX(x2, y2);
            if(arr[i].left > arr[i].right) swap(arr[i].left, arr[i].right);            
        }
        sort(arr, arr + n, cmp);
        ans = 1;
        flag = arr[0].right;
        for(int i = 1; i < n; ++i){
            if(flag < arr[i].left){
                ++ans;
                flag = arr[i].right;
            }else if(flag < arr[i].right) flag = arr[i].right;
        }
        if(!n) printf("1\n"); 
        else printf("%d\n", ans + 1);
    }
    return 0;
}