# [BZOJ1634]&&[Usaco2007 Jan]Protecting the Flowers 护花

## 描述 Description

Farmer John went to cut some wood and left N (2 <= N <= 100,000) cows eating the grass, as usual. When he returned, he found to his horror that the cows were in his garden eating his beautiful flowers. Wanting to minimize the subsequent damage, FJ decided to take immediate action and transport the cows back to their barn. Each cow i is at a location that is Ti minutes (1 <= Ti <= 2,000,000) away from the barn. Furthermore, while waiting for transport, she destroys Di (1 <= Di <= 100) flowers per minute. No matter how hard he tries,FJ can only transport one cow at a time back to the barn. Moving cow i to the barn requires 2*Ti minutes (Ti to get there and Ti to return). Write a program to determine the order in which FJ should pick up the cows so that the total number of flowers destroyed is minimized.

## 输入格式 InputFormat

Line 1: A single integer N.

Lines 2..N+1: Each line contains two space-separated integers, Ti and Di, that describe a single cow’s characteristics.

## 输出格式 OutputFormat

Line 1: A single integer that is the minimum number of destroyed flowers.

13
82 77
97 49
73 77
60 100
94 24
31 74
5 76
24 41
100 70
97 89
38 68
41 93
89 16

362670

Silver

BZOJ 1634

## 代码 Code

``````#include <stdio.h>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;
#define inf 0x7fffffff
struct cow
{
int t,d;
};
cow a[100005];
int i,j,t,n,m,l,r,z,y,x;
long long ans,tot;
{
int s=0;
char ch=getchar();
while (ch<'0' || ch>'9') ch=getchar();
while (ch>='0' && ch<='9') s=s*10+ch-'0',ch=getchar();
return s;
}
inline bool comp(cow a,cow b)
{
return a.t*b.d<a.d*b.t;
}
int main()
{
tot=0;
for (i=1;i<=n;i++)
{