频道栏目
首页 > 程序开发 > 综合编程 > 其他综合 > 正文
Codeforces 383 A. Milking cows
2014-01-22 11:09:33      个评论    来源:码代码的猿猿  
收藏   我要投稿



A. Milking cows time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output

Iahub helps his grandfather at the farm. Today he must milk the cows. There are n cows sitting in a row, numbered from 1 to n from left to right. Each cow is either facing to the left or facing to the right. When Iahub milks a cow, all the cows that see the current cow get scared and lose one unit of the quantity of milk that they can give. A cow facing left sees all the cows with lower indices than her index, and a cow facing right sees all the cows with higher indices than her index. A cow that got scared once can get scared again (and lose one more unit of milk). A cow that has been milked once cannot get scared and lose any more milk. You can assume that a cow never loses all the milk she can give (a cow gives an infinitely amount of milk).

Iahub can decide the order in which he milks the cows. But he must milk each cow exactly once. Iahub wants to lose as little milk as possible. Print the minimum amount of milk that is lost.

Input

The first line contains an integer n (1?≤?n?≤?200000). The second line contains n integers a1, a2, ..., an, where ai is 0 if the cow number i is facing left, and 1 if it is facing right.

Output

Print a single integer, the minimum amount of lost milk.

Please, do not write the %lld specifier to read or write 64-bit integers in С++. It is preferred to use the cin, cout streams or the %I64dspecifier.

Sample test(s) input
4
0 0 1 0
output
1
input
5
1 0 1 0 1
output
3
Note

In the first sample Iahub milks the cows in the following order: cow 3, cow 4, cow 2, cow 1. When he milks cow 3, cow 4 loses 1 unit of milk. After that, no more milk is lost.


#include 
#include 
#include 
#include 

using namespace std;

int main()
{
    long long int n,ans=0,res=0;
    scanf("%I64d",&n);
    for(int i=0;i



点击复制链接 与好友分享!回本站首页
相关TAG标签
上一篇:数据结构与算法16:最小生成树普利姆prim算法
下一篇:Golang Array 数组 和 Slice 切片
相关文章
图文推荐
点击排行

关于我们 | 联系我们 | 广告服务 | 投资合作 | 版权申明 | 在线帮助 | 网站地图 | 作品发布 | Vip技术培训 | 举报中心

版权所有: 红黑联盟--致力于做实用的IT技术学习网站