A804.Cowntact Tracing--Bronze

普及-

USACO

通过率:0%

时间限制:1.00s

内存限制:128MB

题目描述

Farmer John is worried for the health of his cows (conveniently numbered 1N1 \ldots N as always) after an outbreak of the highly contagious bovine disease
COWVID-19.
Recently, Farmer John tested all of his cows and found some of them to be
positive for the disease. Using video footage from inside his barn, he is able
to review recent interactions between pairs of cows --- it turns out that when
cows greet each-other, they shake hooves, a gesture that can unfortunately
spread the infection from one cow to another. Farmer John assembles a time-
stamped list of interacting pairs of cows, with entries of the form (t,x,y)(t, x, y), meaning that at time tt, cow xx shook hooves with cow yy. Farmer John
also knows the following:
(i) Exactly one cow on his farm could have started out carrying the disease
(we'll call this cow "patient zero").
(ii) Once a cow is infected, she passes the infection along with her next KK
hoof shakes (possibly including the same partner cow several times). After
shaking hooves KK times, she no longer passes the infection along with
subsequent hoof shakes (since at this point she realizes she is spreading the
infection and washes her hooves carefully).
(iii) Once a cow is infected, she stays infected.
Unfortunately, Farmer John doesn't know which of his NN cows is patient zero,
nor does he know the value of KK! Please help him narrow down the
possibilities for these unknowns based on his data. It is guaranteed that at
least one possibility is valid.

输入格式

The first line of the input file contains NN (2N1002 \leq N \leq 100) and TT
(1T2501 \leq T \leq 250). The next line contains a string of length NN whose
entries are 0s and 1s, describing the current state of Farmer John's NN cows
--- 0 represents a healthy cow and 1 represents a cow presently with the
disease. Each of the next TT lines describes a record in Farmer John's list
of interactions and consists of three integers tt, xx, and yy, where tt is
a positive integer time of the interaction (t250t \leq 250) and xx and yy are
distinct integers in the range 1N1 \ldots N, indicating which cows shook hands
at time tt. At most one interaction happens at each point in time.

输出格式

Print a single line with three integers xx, yy, and zz, where xx is the
number of possible cows who could have been patient zero, yy is the smallest
possible value of KK consistent with the data, and zz is the largest
possible value of KK consistent with the data (if there is no upper bound on
KK that can be deduced from the data, print "Infinity" for zz). Note that it
might be possible to have K=0K=0.

输入输出样例

  • 输入#1

    4 3
    1100
    7 1 2
    5 2 3
    6 2 4
    

    输出#1

    1 1 Infinity
    

说明/提示

The only candidate for patient zero is cow 1. For all K>0K>0, cow 1 infects cow
2 at time 7, while cows 3 and 4 remain uninfected.

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