ZOJ-3721 Final Exam Arrangement 贪心

　　题目链接：http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemCode=3721

　　容易的贪心题，排个序。。

  1 //STATUS:C++_AC_840MS_6272KB

  2 #include <functional>

  3 #include <algorithm>

  4 #include <iostream>

  5 //#include <ext/rope>

  6 #include <fstream>

  7 #include <sstream>

  8 #include <iomanip>

  9 #include <numeric>

 10 #include <cstring>

 11 #include <cassert>

 12 #include <cstdio>

 13 #include <string>

 14 #include <vector>

 15 #include <bitset>

 16 #include <queue>

 17 #include <stack>

 18 #include <cmath>

 19 #include <ctime>

 20 #include <list>

 21 #include <set>

 22 #include <map>

 23 using namespace std;

 24 //using namespace __gnu_cxx;

 25 //define

 26 #define pii pair<int,int>

 27 #define mem(a,b) memset(a,b,sizeof(a))

 28 #define lson l,mid,rt<<1

 29 #define rson mid+1,r,rt<<1|1

 30 #define PI acos(-1.0)

 31 //typedef

 32 //typedef __int64 LL;

 33 //typedef unsigned __int64 ULL;

 34 //const

 35 const int N=100010;

 36 const int INF=0x3f3f3f3f;

 37 const int MOD=100000,STA=8000010;

 38 //const LL LNF=1LL<<60;

 39 const double EPS=1e-8;

 40 const double OO=1e15;

 41 const int dx[4]={-1,0,1,0};

 42 const int dy[4]={0,1,0,-1};

 43 const int day[13]={0,31,28,31,30,31,30,31,31,30,31,30,31};

 44 //Daily Use ...

 45 inline int sign(double x){return (x>EPS)-(x<-EPS);}

 46 template<class T> T gcd(T a,T b){return b?gcd(b,a%b):a;}

 47 template<class T> T lcm(T a,T b){return a/gcd(a,b)*b;}

 48 template<class T> inline T lcm(T a,T b,T d){return a/d*b;}

 49 template<class T> inline T Min(T a,T b){return a<b?a:b;}

 50 template<class T> inline T Max(T a,T b){return a>b?a:b;}

 51 template<class T> inline T Min(T a,T b,T c){return min(min(a, b),c);}

 52 template<class T> inline T Max(T a,T b,T c){return max(max(a, b),c);}

 53 template<class T> inline T Min(T a,T b,T c,T d){return min(min(a, b),min(c,d));}

 54 template<class T> inline T Max(T a,T b,T c,T d){return max(max(a, b),max(c,d));}

 55 //End

 56 

 57 struct Node{

 58     int l,r;

 59     int idx;

 60     bool operator < (const Node &a)const {

 61         return l!=a.l?l<a.l:r<a.r;

 62     }

 63 }p[N];

 64 int cnt[N];

 65 vector<int> q[N];

 66 int n;

 67 

 68 int main()

 69 {

 70   //  freopen("in.txt","r",stdin);

 71     int i,j,tot,R;

 72     while(~scanf("%d",&n))

 73     {

 74         tot=0;

 75         mem(cnt,0);

 76         for(i=0;i<=n;i++)q[i].clear();

 77         for(i=0;i<n;i++){

 78             scanf("%d%d",&p[i].l,&p[i].r);

 79             p[i].idx=i+1;

 80         }

 81         sort(p,p+n);

 82 

 83         R=-1;

 84         for(i=0;i<n;i++){

 85             if(p[i].l>=R){

 86                 tot++;

 87                 R=p[i].r;

 88             }

 89             R=Min(R,p[i].r);

 90             q[tot].push_back(p[i].idx);

 91             cnt[tot]++;

 92         }

 93 

 94         printf("%d\n",tot);

 95         for(i=1;i<=tot;i++){

 96             printf("%d",q[i][0]);

 97             for(j=1;j<cnt[i];j++)

 98                 printf(" %d",q[i][j]);

 99             putchar('\n');

100         }

101         putchar('\n');

102     }

103     return 0;

104 }