Time Limit: 10 Sec Memory Limit: 64 MB
Submit: 566 Solved: 314
Oh those picky N (1 <= N <= 50,000) cows! They are so picky that each one will only be milked over some precise time interval A..B (1 <= A <= B <= 1,000,000), which includes both times A and B. Obviously, FJ must create a reservation system to determine which stall each cow can be assigned for her milking time. Of course, no cow will share such a private moment with other cows. Help FJ by determining: * The minimum number of stalls required in the barn so that each cow can have her private milking period * An assignment of cows to these stalls over time
有N头牛,每头牛有个喝水时间,这段时间它将专用一个Stall 现在给出每头牛的喝水时间段,问至少要多少个Stall才能满足它们的要求
* Line 1: A single integer, N
* Lines 2..N+1: Line i+1 describes cow i's milking interval with two space-separated integers.
* Line 1: The minimum number of stalls the barn must have.
* Lines 2..N+1: Line i+1 describes the stall to which cow i will be assigned for her milking period.
5 1 10 2 4 3 6 5 8 4 7
4 OUTPUT DETAILS: Here's a graphical schedule for this output: Time 1 2 3 4 5 6 7 8 9 10 Stall 1 c1>>>>>>>>>>>>>>>>>>>>>>>>>>> Stall 2 .. c2>>>>>> c4>>>>>>>>> .. .. Stall 3 .. .. c3>>>>>>>>> .. .. .. .. Stall 4 .. .. .. c5>>>>>>>>> .. .. .. Other outputs using the same number of stalls are possible.
不妨试下这个数据,对于按结束点SORT,再GREEDY的做法 1 3 5 7 6 9 10 11 8 12 4 13 正确的输出应该是3
题解: 呵呵呵呵呵,逗比的我一开始看到N<=50000,然后就开了100000的数组,然后欢乐满满地RE(TuT),然后加了一个0,AC。。。好啦,这个题就是统计一下同一时间最多有多少只牛在同时进行喝水即可,只要想办法用线性的时间做到维护当前值即可。。。
1 var
2 i,j,k,l,m,n:longint;
3 a:array[0..1050000] of longint;
4 begin
5 readln(n);
6 fillchar(a,sizeof(a),0);
7 for i:=1 to n do
8 begin
9 readln(j,k);
10 inc(a[j]);
11 dec(a[k+1]);
12 end;
13 j:=0;l:=0;
14 for i:=1 to 1000000 do
15 begin
16 j:=j+a[i];
17 if j>l then l:=j;
18 end;
19 writeln(l);
20 end.
21