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#include <stdio.h> |
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#include <iostream> |
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#include <algorithm> |
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using namespace std; |
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struct line{ |
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int s,e; |
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bool operator<(const line &t)const{ |
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if(s!=t.s)return s<t.s; |
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else return e>t.e; |
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} |
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}; |
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line a[100001]; |
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bool ch[100001]; |
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int main(){ |
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int T,i,j,k,m,n,cnt,cur; |
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cin>>T; |
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while(T--){ |
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cin>>m; |
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n=0; |
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while(scanf("%d%d",&a[n].s,&a[n].e)==2 && (a[n].s||a[n].e)) |
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ch[n++]=0; |
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sort(a,a+n); |
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cur=cnt=0; |
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for(i=0;i<n && cur<m && a[i].s<=cur;i++){ |
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for(k=j=i;j<n && a[j].s<=cur;j++) |
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if(a[j].e>a[k].e) |
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k=j; |
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ch[k]=1; |
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cnt++; |
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cur=a[k].e; |
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i=k; |
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} |
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if(cur>=m){ |
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cout<<cnt<<endl; |
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for(i=0;i<n && cnt;i++) |
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if(ch[i]) |
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printf("%d %d\n",a[i].s,a[i].e),cnt--; |
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}else |
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cout<<0<<endl; |
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if(T)cout<<endl; |
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} |
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} |
