记录编号 |
195884 |
评测结果 |
AAAAAAAAAAAA |
题目名称 |
[USACO Jan07]考试 |
最终得分 |
100 |
用户昵称 |
dashgua |
是否通过 |
通过 |
代码语言 |
C++ |
运行时间 |
0.026 s |
提交时间 |
2015-10-20 01:37:14 |
内存使用 |
2.21 MiB |
显示代码纯文本
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <ctime>
#include <vector>
#include <utility>
#include <stack>
#include <queue>
#include <map>
#include <iostream>
#include <algorithm>
template<class Num>void read(Num &x)
{
char c; int flag = 1;
while((c = getchar()) < '0' || c > '9')
if(c == '-') flag *= -1;
x = c - '0';
while((c = getchar()) >= '0' && c <= '9')
x = (x<<3) + (x<<1) + (c-'0');
x *= flag;
}
template<class Num>void write(Num x)
{
if(!x) {putchar('0');return;}
if(x < 0) putchar('-'), x = -x;
static char s[20];int sl = 0;
while(x) s[sl++] = x%10 + '0',x /= 10;
while(sl) putchar(s[--sl]);
}
const int maxn = 50010;
#define X second.first
#define Y second.second
#define R first
const double lim = 40050;
int n;
std::pair<double, std::pair<int,int> >node[maxn];
double low[maxn], high[maxn];
double G[maxn];
void init()
{
int x, y;
read(n);
for(int i = 1; i <= n; i++)
{
read(y), read(x);
node[i] = std::make_pair((double) y / x , std::make_pair(x, y));
}
}
double slope(int a,int b)
{
return (double)(node[b].Y - node[a].Y) / (node[b].X - node[a].X);
}
void solve()
{
static int line[maxn];
int f = 0, r = 0, cnt = 0;
std::sort(node + 1, node + n + 1);
//std::greater<std::pair<double, std::pair<int,int> > >()
for(int i = n, tx = 0, ty = 0; i >= 1; i--)
{
tx += node[i].X, ty += node[i].Y;
G[i] = (double) ty / tx;
}
f = r = 0;
for(int i = 1; i < n; i++)
{
while(f != r && node[line[r - 1]].X >= node[i].X) r--;
while(r - f >= 2 && slope(line[r - 2], i) > slope(line[r - 2], line[r - 1])) r--;
line[r++] = i;
while(r - f >= 2 && slope(line[r - 2], line[r - 1]) < G[i + 1]) r--;
high[i] = node[line[r - 1]].Y - G[i + 1] * node[line[r - 1]].X;
}
f = r = 0;
for(int i = n; i > 1; i--)
{
while(f != r && node[line[r - 1]].X <= node[i].X) r--;
while(r - f >= 2 && slope(line[r - 2], i) > slope(line[r - 2], line[r - 1])) r--;
line[r++] = i;
while(r - f >= 2 && slope(line[r - 2], line[r - 1]) < G[i]) r--;
low[i] = node[line[r - 1]].Y - G[i] * node[line[r - 1]].X;
}
for(int i = 1; i < n; i++)
cnt += low[i + 1] < high[i];
write(cnt), puts("");
for(int i = 1; i < n; i++)
if(low[i + 1] < high[i])
write(i), puts("");
}
int main()
{
freopen("schul.in","r",stdin);
freopen("schul.out","w",stdout);
init();
solve();
fclose(stdin);
fclose(stdout);
return 0;
}