#include <iostream>#include <algorithm>#include <map>#include <vector>#include <cmath>#include <cstring>#include <cstdlib>#include <cstdio>using namespace std;#define FOR(i,a,b) for(int i=a;i<(b);i++)const int N=202000;struct Stamp{ int t,id; bool type;}Time[2*N];struct Interval{ int s,t;}L[N];int n;bool used[N];bool comp(const Stamp&a, const Stamp&b){ if(a.t==b.t) return a.type; return a.t<b.t;}vector<int> ans[N];int main(){ while(scanf("%d",&n)==1) { FOR(i,0,n) scanf("%d%d",&L[i].s,&L[i].t); FOR(i,0,n) { int a=i<<1,b=a+1; Time[a].t=L[i].s; Time[a].id=i+1; Time[a].type=0; Time[b].t=L[i].t; Time[b].id=i+1; Time[b].type=1; } sort(Time,Time+2*n,comp); int tot=0;ans[0].clear(); memset(used,0,sizeof(used)); int nn=n<<1; FOR(i,0,nn) { if(!used[Time[i].id]) { if (Time[i].type) { for(vector<int>::iterator it=ans[tot].begin();it!=ans[tot].end();it++) { used[*it] = true; } ans[++tot].clear(); continue; } } if (!Time[i].type) ans[tot].push_back(Time[i].id); } printf("%dn", tot); FOR(i,0,tot) { vector<int>::iterator it=ans[i].begin(); printf("%d", *it); for(it++;it!=ans[i].end();it++) printf(" %d", *it); printf("n"); } printf("n"); }}
