mirror of
https://github.com/Kiritow/OJ-Problems-Source.git
synced 2024-03-22 13:11:29 +08:00
52 lines
1.1 KiB
C++
52 lines
1.1 KiB
C++
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#include <list>
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#include <map>
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#include <set>
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#include <queue>
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#include <string>
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#include <deque>
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#include <stack>
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#include <algorithm>
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#include <iostream>
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#include <iomanip>
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#include <cstdio>
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#include <cmath>
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#include <cstdlib>
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#include <limits.h>
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#include <time.h>
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#include <string.h>
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using namespace std;
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#define LL long long
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#define PI acos(-1.0)
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#define Max INT_MAX
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#define Min INT_MIN
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#define eps 1e-8
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#define N 201
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bool g[N][N];
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bool gg[N][N];
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int main(){
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int n,m;
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while(scanf("%d%d",&n,&m)!=EOF){
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int i,j,k;
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memset(g,false,sizeof(g));
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memset(gg,false,sizeof(gg));
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while(m--){
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int a,b;
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scanf("%d%d",&a,&b);
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g[a][b]=true;
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}
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int res=0;
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for(i=1;i<=n;i++)
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for(j=1;j<=n;j++)
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for(k=1;k<=n;k++)
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if(g[j][i] && g[i][k]){
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g[j][k]=gg[j][k]=true;
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}
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for(i=1;i<=n;i++)
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for(j=i+1;j<=n;j++)
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if(gg[i][j] || gg[j][i])
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res++;
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printf("%d\n",n*(n-1)/2-res);
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}
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return 0;
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}
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