codeforces Wunder Fund Round 2016 (Div. 1 + Div. 2 combined) C. Constellation

C. Constellation

Cat Noku has obtained a map of the night sky. On this map, he found a constellation with n stars numbered from 1 to n. For each i, thei-th star is located at coordinates (xi, yi). No two stars are located at the same position.

In the evening Noku is going to take a look at the night sky. He would like to find three distinct stars and form a triangle. The triangle must have positive area. In addition, all other stars must lie strictly outside of this triangle. He is having trouble finding the answer and would like your help. Your job is to find the indices of three stars that would form a triangle that satisfies all the conditions.

It is guaranteed that there is no line such that all stars lie on that line. It can be proven that if the previous condition is satisfied, there exists a solution to this problem.

Input

The first line of the input contains a single integer n (3 ≤ n ≤ 100 000).

Each of the next n lines contains two integers xi and yi ( - 109 ≤ xi, yi ≤ 109).

It is guaranteed that no two stars lie at the same point, and there does not exist a line such that all stars lie on that line.

Output

Print three distinct integers on a single line — the indices of the three points that form a triangle that satisfies the conditions stated in the problem.

If there are multiple possible answers, you may print any of them.

Sample test(s)

input

30 11 01 1

output

1 2 3

input

50 00 22 02 21 1

output

1 3 5

Note

In the first sample, we can print the three indices in any order.

In the second sample, we have the following picture.

Note that the triangle formed by starts 1, 4 and 3 doesn‘t satisfy the conditions stated in the problem, as point 5 is not strictly outside of this triangle (it lies on it‘s border).

 1 /*先排序,然后判断相邻三个点不共线就行了*/
 2 #include<cstdio>
 3 #include<cstring>
 4 #include<map>
 5 #include<stack>
 6 #include<iostream>
 7 #include<algorithm>
 8 using namespace std;
 9 typedef long long ll;
10 const int maxn=1e5+5;
11 struct point
12 {
13     int id;
14     int x,y;
15 }p[maxn];
16 bool cmp(point a,point b)
17 {
18     return a.x==b.x?a.y<b.y:a.x<b.x;
19 }
20 bool check(point a,point b,point c)
21 {
22     if((a.y-b.y)*1.0/(a.x-b.x)==(b.y-c.y)*1.0/(b.x-c.x))return false;
23     return true;
24 }
25 int main()
26 {
27     int n,i;
28     scanf("%d",&n);
29     for(int i=0;i<n;i++)
30         scanf("%d%d",&p[i].x,&p[i].y),p[i].id=i+1;
31     sort(p,p+n,cmp);
32     for(i=2;i<n;i++)
33         if(check(p[i],p[i-1],p[i-2]))break;
34     printf("%d %d %d\n",p[i-2].id,p[i-1].id,p[i].id);
35     return 0;
36 }
时间: 2024-10-27 17:53:04

codeforces Wunder Fund Round 2016 (Div. 1 + Div. 2 combined) C. Constellation的相关文章

codeforces Wunder Fund Round 2016 (Div. 1 + Div. 2 combined) B Guess the Permutation

B. Guess the Permutation Bob has a permutation of integers from 1 to n. Denote this permutation as p. The i-th element of p will be denoted as pi. For all pairs of distinct integers i, j between 1 and n, he wrote the number ai, j = min(pi, pj). He wr

Wunder Fund Round 2016 (Div. 1 + Div. 2 combined)

现在水平真的不够.只能够做做水题 A. Slime Combining 题意:就是给n个1给你.两个相同的数可以合并成一个数,比如说有两个相同的v,合并后的值就是v+1 思路:直接模拟栈 1 #include<iostream> 2 #include<algorithm> 3 #include<stack> 4 using namespace std; 5 int num[10000]; 6 int main() 7 { 8 int n; 9 while(cin >

Educational Codeforces Round 36 (Rated for Div. 2)

Educational Codeforces Round 36 (Rated for Div. 2) F. Imbalance Value of a Tree You are given a tree T consisting of n vertices. A number is written on each vertex; the number written on vertex i is ai. Let's denote the function I(x,?y) as the differ

Educational Codeforces Round 36 (Rated for Div. 2) 题解

Educational Codeforces Round 36 (Rated for Div. 2) 题目的质量很不错(不看题解做不出来,笑 Codeforces 920C 题意 给定一个\(1\)到\(n\)组成的数组,只可以交换某些相邻的位置,问是否可以将数组调整为升序的 解题思路 首先如果每个数都能通过交换到它应该到的位置,那么就可以调整为升序的. 但实际上交换是对称的,如果应该在的位置在当前位置前方的数都交换完成,那么整体就是排好序的,因为不可能所有不在相应位置的数都在相应位置的后方.

Codeforces Educational Codeforces Round 44 (Rated for Div. 2) E. Pencils and Boxes

Codeforces Educational Codeforces Round 44 (Rated for Div. 2) E. Pencils and Boxes 题目连接: http://codeforces.com/contest/985/problem/E Description Mishka received a gift of multicolored pencils for his birthday! Unfortunately he lives in a monochrome w

Codeforces Round #504 (rated, Div. 1 + Div. 2, based on VK Cup 2018 Final) A. Single Wildcard Pattern Matching B. Pair of Toys C. Bracket Subsequence D. Array Restoration-区间查询最值(RMQ(ST))

Codeforces Round #504 (rated, Div. 1 + Div. 2, based on VK Cup 2018 Final) A. Single Wildcard Pattern Matching 题意就是匹配字符的题目,打比赛的时候没有看到只有一个" * ",然后就写挫了,被hack了,被hack的点就是判一下只有一个" * ". 1 //A 2 #include<iostream> 3 #include<cstdio&g

Educational Codeforces Round 55 (Rated for Div. 2)

Educational Codeforces Round 55 (Rated for Div. 2) 链接 A Vasya and Book 傻逼题..注意判边界. #include<cstdio> #include<cstring> #include<algorithm> #include<queue> #include<set> #include<map> #include<vector> #include<cm

Educational Codeforces Round 57 (Rated for Div. 2)

get人生第二场CF! 成绩:(exACM) rank858 AC3/7 Penalty57 rating1648(+52) 题目:Educational Codeforces Round 57 (Rated for Div. 2) 错题题解: D. Easy Problem E. The Top Scorer F. Inversion Expectation G. Lucky Tickets 原文地址:https://www.cnblogs.com/xht37/p/10198321.html

Educational Codeforces Round 58 (Rated for Div. 2)(待更新)

get人生第七场CF! 成绩:(exACM) rank AC3/7 Penalty104 rating() 题目:Educational Codeforces Round 58 (Rated for Div. 2) 错题题解: C. Division and Union 原文地址:https://www.cnblogs.com/xht37/p/10260260.html