POJ 2419 Forests

Description

If a tree falls in the forest, and there's nobody there to hear, does it make a sound? This classic conundrum was coined by George Berkeley (1685-1753), the Bishop and influential Irish philosopher whose primary philosophical achievement is the advancement of what has come to be called subjective idealism. He wrote a number of works, of which the most widely-read are Treatise Concerning the Principles of Human Knowledge (1710) and Three Dialogues between Hylas and Philonous (1713) (Philonous, the "lover of the mind," representing Berkeley himself).

Input

A forest contains T trees numbered from 1 to T and P people numbered from 1 to P. Standard input consists of a line containing P and T followed by several lines, containing a pair of integers i and j, indicating that person i has heard tree j fall.

Output

People may have different opinions as to which trees, according to Berkeley, have made a sound. Output how many different opinions are represented in the input? Two people hold the same opinion only if they hear exactly the same set of trees. You may assume that P < 100 and T < 100.

Sample Input

3 41 23 31 32 23 22 4

Sample Output

2

Source

Waterloo Local 2002.01.26

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二进制~

（其实我也不知道该分为什么……明明就是大暴力嘛……

用两个long long记录每个人听见的树，然后暴力比对就可以了~

读入优化不可以用在EOF里面啊！

#include<cstdio>#include<iostream>#include<algorithm>using namespace std;#define ll long longint n,m,tot,x,y;ll a[101][2],num[101][2];bool flag;int read(){int x=0,f=1;char ch=getchar();while(ch<'0' || ch>'9') {if(ch=='-') f=-1;ch=getchar();}while(ch>='0' && ch<='9') {x=(x<<1)+(x<<3)+ch-'0';ch=getchar();}return x*f; }int main(){n=read();m=read();while(scanf("%d",&x)!=EOF){y=read();y--;if(y<50) a[x][0]|=(1<<y);else a[x][1]|=(1<<(y-50));}for(int i=1;i<=n;i++){flag=0;for(int j=1;j<=tot;j++)  if(a[i][0]==num[j][0] && a[i][1]==num[j][1])  {flag=1;break;  }if(!flag) num[++tot][0]=a[i][0],num[tot][1]=a[i][1];}printf("%d\n",tot);return 0;}