【April Fools Day Contest 2014G】【愚人节脑洞】On a plane 输出纵坐标平均值
G. On a plane
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output
Input
The first line contains a single integer n (1 ≤ n ≤ 1000) — the number of points on a plane.
Each of the next n lines contains two real coordinates xi and yi of the 
point, specified with exactly 2 fractional digits. All coordinates are between - 1000 and 1000, inclusive.
Output
Output a single real number θ — the answer to the problem statement. The absolute or relative error of your answer should be at most10 - 2.
Examples
input
8 -2.14 2.06 -1.14 2.04 -2.16 1.46 -2.14 0.70 -1.42 0.40 -0.94 -0.48 -1.42 -1.28 -2.16 -1.62
output
5.410
input
5 2.26 1.44 2.28 0.64 2.30 -0.30 1.58 0.66 3.24 0.66
output
5.620
input
8 6.98 2.06 6.40 1.12 5.98 0.24 5.54 -0.60 7.16 0.30 7.82 1.24 8.34 0.24 8.74 -0.76
output
5.480
input
5 10.44 2.06 10.90 0.80 11.48 -0.48 12.06 0.76 12.54 2.06
output
6.040
input
8 16.94 2.42 15.72 2.38 14.82 1.58 14.88 0.50 15.76 -0.16 16.86 -0.20 17.00 0.88 16.40 0.92
output
6.040
input
7 20.62 3.00 21.06 2.28 21.56 1.36 21.66 0.56 21.64 -0.52 22.14 2.32 22.62 3.04
output
6.720
#include<stdio.h>
#include<iostream>
#include<string.h>
#include<string>
#include<ctype.h>
#include<math.h>
#include<set>
#include<map>
#include<vector>
#include<queue>
#include<bitset>
#include<algorithm>
#include<time.h>
using namespace std;
void fre() { freopen("c://test//input.in", "r", stdin); freopen("c://test//output.out", "w", stdout); }
#define MS(x,y) memset(x,y,sizeof(x))
#define MC(x,y) memcpy(x,y,sizeof(x))
#define MP(x,y) make_pair(x,y)
#define ls o<<1
#define rs o<<1|1
typedef long long LL;
typedef unsigned long long UL;
typedef unsigned int UI;
template <class T1, class T2>inline void gmax(T1 &a, T2 b) { if (b>a)a = b; }
template <class T1, class T2>inline void gmin(T1 &a, T2 b) { if (b<a)a = b; }
const int N = 0, M = 0, Z = 1e9 + 7, ms63 = 0x3f3f3f3f;
int n;
int main()
{
while (~scanf("%d", &n))
{
double sum = 0, x;
for (int i = 1; i <= n; ++i)
{
scanf("%*lf%lf", &x);
sum += x;
}
printf("%.3f\n", 5 + sum / n);
}
return 0;
}
/*
【trick&&吐槽】
能否想到只与第二维相关呢？
毕竟一些信息是干扰信息。常有的。
*/