C. Nearest vectors(卡精度,恶心)

/* ***********************************************
Author        :xdlove
Created Time  :2015年11月13日 星期五 23时24分49秒
File Name     :xdlove/codeforces/Educational_Codeforces_Round_1/C/C.cpp
************************************************ */

#pragma comment(linker, "/STACK:1024000000,1024000000")
#include <stdio.h>
#include <string.h>
#include <iostream>
#include <algorithm>
#include <memory.h>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <string>
#include <math.h>
#include <stdlib.h>
#include <time.h>

using namespace std;

#define REP_ab(i,a,b) for(int i = a; i <= b; i++)
#define REP(i, n) for(int i = 0; i < n; i++)
#define REP_1(i,n) for(int i = 1; i <= n; i++)
#define DEP(i,n) for(int i = n - 1; i >= 0; i--)
#define DEP_N(i,n) for(int i = n; i >= 1; i--)
#define CPY(A,B) memcpy(A,B,sizeof(B))
#define MEM(A) memset(A,0,sizeof(A))
#define MEM_1(A) memset(A,-1,sizeof(A))
#define MEM_INF(A) memset(A,0x3f,sizeof(A))
#define MEM_INFLL(A) memset(A,0x3f3f,sizeof(A))
#define mid (((l + r) >> 1))
#define lson l, mid, u << 1
#define rson mid + 1, r, u << 1 | 1
#define ls (u << 1)
#define rs (u << 1 | 1)

typedef long long ll;
typedef unsigned long long ull;
const int INF = 0x3f3f3f3f;
const ll INFLL = 0x3f3f3f3f3f3f3f3f;
const int MAXN = 1e5 + 5;
const int MAXM = MAXN;
const int mod = 1e9 + 7;
const long double pi = acos(-1.0);
const long double eps = 1e-8;

struct Point
{
long double k;
int id;
bool operator < (const Point &a) const
{
return k < a.k;
}
}p[MAXN];

int main()
{
//freopen("in.txt","r",stdin);
//freopen("out.txt","w",stdout);
int n;
cin>>n;
REP(i,n)
{
int x,y;
scanf("%d %d",&x,&y);
p[i].k = atan2(y,x);
p[i].id = i + 1;
}
sort(p,p + n);
long double ans;
if(p[0].k < 0) ans = p[0].k + 2 * pi - p[n - 1].k;
else ans = p[n - 1].k - p[0].k;
int a1 = p[n - 1].id,a2 = p[0].id;
for(int i = 1; i < n; i++)
{
long double tp = p[i].k - p[i - 1].k;
if(tp  < ans)
{
ans = tp;
a1 = p[i].id;
a2 = p[i - 1].id;
}
}
cout<<a1<<" "<<a2<<endl;
return 0;
}