第十四届蓝桥杯集训——练习解题阶段(无序阶段)-ALGO-967 共线

#include <stdio.h>
#include <stdlib.h>
typedef struct node{
	int x;
	int y;	
}Node;
int Max(int a,int b){
	return a>b?a:b;
}
int main() {
    int n;
    scanf("%d",&n);
    Node *a=(Node*)malloc(sizeof(Node)*n);
    int i;
    for(i=0;i<n;i++){
    	scanf("%d %d",&a[i].x,&a[i].y);
	}
	int j;
	int count=0;
	int res=0;
	if(n<3){
		printf("%d",n);
	}else{
		for(i=1;i<n;i++){
		   int x=a[i].x;
		   int y=a[i].y;
		   int xx=x-a[i-1].x;
		   int yy=y-a[i-1].y;
		   for(j=0;j<n;j++){
		   	 if((a[j].x-x)*yy==(a[j].y-y)*xx){
		   	 	  count++;
				}
		   }
		   res=Max(res,count);
		   count=0;	
		}
		printf("%d",res);
	}

	return 0;
}

#include<stdio.h>
struct qk
{
	int x,y;
}k[1511];
int main()
{
	int i,n,f,max=0,j,t1,t2;
	scanf("%d",&n);
	for(i=0;i<n;i++)
	{
		scanf("%d %d",&k[i].x,&k[i].y);
	}
	for(i=0;i<n;i++)
	{
		f=0;
		j=i+1;
		t1=k[i].x-k[j].x;
		t2=k[i].y-k[j].y;
		for(j=0;j<n;j++)
		{
			if(((k[i].y-k[j].y)*t1)==((k[i].x-k[j].x)*t2))f++;
		}if(f>max)max=f;
	}
	printf("%d\n",max);
	return 0;
}

import java.io.*;

public class Main {
	public static void main(String[] args) throws NumberFormatException, IOException {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		int n=Integer.parseInt(br.readLine());
	  int arr [][]=new int[2] [n];
	  for (int i = 0; i <n; i++) {
		String [] str=br.readLine().split(" ");
		arr[0][i]=Integer.parseInt(str[0]);
		arr[1][i]=Integer.parseInt(str[1]);
	}
	  if (n<3) {
		System.out.println(n);
		return;
	}
	  int res=0;
	  for (int i = 1; i < n; i++) {
		int xx=arr[0][i]-arr[0][i-1];
		int yy=arr[1][i]-arr[1][i-1];
		int count=0;
		for (int j = 0; j <n; j++) {
			if ((arr[0][j]-arr[0][i])*yy==(arr[1][j]-arr[1][i])*xx) {
				count++;
			}
		}
		res=Math.max(res,count);
	}
	  System.out.println(res);
	}
}

class Point:
    def __init__(self,x,y):
        self.x=x
        self.y=y

def same_line():
    res=0
    for i in range(0,n):
        x=pos[i].x
        y=pos[i].y
        xx=x-pos[i-1].x
        yy=y-pos[i-1].y
        count=0
        for j in range(n):
            if (pos[j].x-x)*yy==(pos[j].y-y)*xx:
                count+=1
        res=max(res,count)
    print(res)
    pass
n=int(input())
pos=[]
for i in range(n):
    x,y=map(int, input().split())
    pos.append(Point(x,y))
same_line()