[USACO06FEB]摊位预订Stall Reservations

题目描述

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 periodAn assignment of cows to these stalls over timeMany answers are correct for each test dataset; a program will grade your answer. 约翰的N(l

输入输出格式

输入格式


Line 1: A single integer, N Lines 2..N+1: Line i+1 describes cow i's milking interval with two space-separated integers.

输出格式


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.

输入输出样例

输入样例 #1

5
1 10
2 4
3 6
5 8
4 7

输出样例 #1

4
1
2
3
2
4

说明

Explanation of the sample: 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. 由@FlierKing提供spj