A828.Robot Instructions--Silver

提高+/省选-

USACO

通过率:0%

时间限制:1.00s

内存限制:128MB

题目描述

Bessie is learning how to control a robot she has recently received as a gift.
The robot begins at point (0,0)(0, 0) on the coordinate plane and Bessie wants
the robot to end at point (xg,yg)(x_g, y_g). Bessie initially has a list of NN
(1N401\le N\le 40) instructions to give to the robot, the ii-th of which will
move the robot xix_i units right and yiy_i units up (or left or down when
xix_i and yiy_i are negative, respectively).
For each KK from 11 to NN, help Bessie count the number of ways she can
select KK instructions from the original NN such that after the KK
instructions are executed, the robot will end at point (xg,yg)(x_g, y_g).
Note: the time and memory limits for this problem are 4s and 512MB, twice
the defaults.

输入格式

The first line contains NN. The next line contains xgx_g and ygy_g, each in
the range 109109-10^9 \ldots 10^9. The final NN lines describe the instructions.
Each line has two integers xix_i and yiy_i, also in the range 109109-10^9 \ldots 10^9.
It is guaranteed that (xg,yg)(0,0)(x_g,y_g)\neq (0,0) and (xi,yi)(0,0)(x_i,y_i)\neq (0,0) for all
ii.

输出格式

Print NN lines, the number of ways Bessie can select KK instructions from
the original NN for each KK from 11 to NN.

输入输出样例

  • 输入#1

    7
    5 10
    -2 0
    3 0
    4 0
    5 0
    0 10
    0 -10
    0 10
    

    输出#1

    0
    2
    0
    3
    0
    1
    0
    

说明/提示

In this example, there are six ways Bessie can select the instructions:
(-2,0) (3,0) (4,0) (0,10) (0,-10) (0,10) (1 2 3 5 6 7)
(-2,0) (3,0) (4,0) (0,10) (1 2 3 5)
(-2,0) (3,0) (4,0) (0,10) (1 2 3 7)
(5,0) (0,10) (0,-10) (0,10) (4 5 6 7)
(5,0) (0,10) (4 5)
(5,0) (0,10) (4 7)
For the first way, the robot's path looks as follows:
(0,0) -> (-2,0) -> (1,0) -> (5,0) -> (5,10) -> (5,0) -> (5,10)

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