#!/usr/bin/env perl
# https://theweeklychallenge.org/blog/perl-weekly-challenge-337/#TASK2
#
# Task 2: Odd Matrix
# ==================
#
# You are given row and col, also a list of positions in the matrix.
#
# Write a script to perform action on each location (0-indexed) as provided in
# the list and find out the total odd valued cells.
#
# For each location (r, c), do both of the following:
#
# a) Increment by 1 all the cells on row r.
# b) Increment by 1 all the cells on column c.
#
#
## Example 1
##
## Input: $row = 2, $col = 3, @locations = ([0,1],[1,1])
## Output: 6
##
## Initial:
## [ 0 0 0 ]
## [ 0 0 0 ]
##
## Apply [0,1]:
## Increment row 0:
## Before     After
## [ 0 0 0 ]  [ 1 1 1 ]
## [ 0 0 0 ]  [ 0 0 0 ]
## Increment col 1:
## Before     After
## [ 1 1 1 ]  [ 1 2 1 ]
## [ 0 0 0 ]  [ 0 1 0 ]
##
## Apply [1,1]:
## Increment row 1:
## Before     After
## [ 1 2 1 ]  [ 1 2 1 ]
## [ 0 1 0 ]  [ 1 2 1 ]
## Increment col 1:
## Before     After
## [ 1 2 1 ]  [ 1 3 1 ]
## [ 1 2 1 ]  [ 1 3 1 ]
##
## Final:
## [ 1 3 1 ]
## [ 1 3 1 ]
#
#
## Example 2
##
## Input: $row = 2, $col = 2, @locations = ([1,1],[0,0])
## Output: 0
##
## Initial:
## [ 0 0 ]
## [ 0 0 ]
##
## Apply [1,1]:
## Increment row 1:
## Before    After
## [ 0 0 ]   [ 0 0 ]
## [ 0 0 ]   [ 1 1 ]
## Increment col 1:
## Before    After
## [ 0 0 ]   [ 0 1 ]
## [ 1 1 ]   [ 1 2 ]
##
## Apply [0,0]:
## Increment row 0:
## Before    After
## [ 0 1 ]   [ 1 2 ]
## [ 1 2 ]   [ 1 2 ]
## Increment col 0:
## Before    After
## [ 1 2 ]   [ 2 2 ]
## [ 1 2 ]   [ 2 2 ]
##
## Final:
## [ 2 2 ]
## [ 2 2 ]
#
#
## Example 3
##
## Input: $row = 3, $col = 3, @locations = ([0,0],[1,2],[2,1])
## Output: 0
##
## Initial:
## [ 0 0 0 ]
## [ 0 0 0 ]
## [ 0 0 0 ]
##
## Apply [0,0]:
## Increment row 0:
## Before     After
## [ 0 0 0 ]  [ 1 1 1 ]
## [ 0 0 0 ]  [ 0 0 0 ]
## [ 0 0 0 ]  [ 0 0 0 ]
## Increment col 0:
## Before     After
## [ 1 1 1 ]  [ 2 1 1 ]
## [ 0 0 0 ]  [ 1 0 0 ]
## [ 0 0 0 ]  [ 1 0 0 ]
##
## Apply [1,2]:
## Increment row 1:
## Before     After
## [ 2 1 1 ]  [ 2 1 1 ]
## [ 1 0 0 ]  [ 2 1 1 ]
## [ 1 0 0 ]  [ 1 0 0 ]
## Increment col 2:
## Before     After
## [ 2 1 1 ]  [ 2 1 2 ]
## [ 2 1 1 ]  [ 2 1 2 ]
## [ 1 0 0 ]  [ 1 0 1 ]
##
## Apply [2,1]:
## Increment row 2:
## Before     After
## [ 2 1 2 ]  [ 2 1 2 ]
## [ 2 1 2 ]  [ 2 1 2 ]
## [ 1 0 1 ]  [ 2 1 2 ]
## Increment col 1:
## Before     After
## [ 2 1 2 ]  [ 2 2 2 ]
## [ 2 1 2 ]  [ 2 2 2 ]
## [ 2 1 2 ]  [ 2 2 2 ]
##
## Final:
## [ 2 2 2 ]
## [ 2 2 2 ]
## [ 2 2 2 ]
#
#
## Example 4
##
## Input: $row = 1, $col = 5, @locations = ([0,2],[0,4])
## Output: 2
##
## Initial:
## [ 0 0 0 0 0 ]
##
## Apply [0,2]:
## Increment row 0:
## Before         After
## [ 0 0 0 0 0 ]  [ 1 1 1 1 1 ]
## Increment col 2:
## Before         After
## [ 1 1 1 1 1 ]  [ 1 1 2 1 1 ]
##
## Apply [0,4]:
## Increment row 0:
## Before         After
## [ 1 1 2 1 1 ]  [ 2 2 3 2 2 ]
## Increment col 4:
## Before         After
## [ 2 2 3 2 2 ]  [ 2 2 3 2 3 ]
##
## Final:
## [ 2 2 3 2 3 ]
#
#
## Example 5
##
## Input: $row = 4, $col = 2, @locations = ([1,0],[3,1],[2,0],[0,1])
## Output: 8
##
## Initial:
## [ 0 0 ]
## [ 0 0 ]
## [ 0 0 ]
## [ 0 0 ]
##
## Apply [1,0]:
## Increment row 1:
## Before     After
## [ 0 0 ]    [ 0 0 ]
## [ 0 0 ]    [ 1 1 ]
## [ 0 0 ]    [ 0 0 ]
## [ 0 0 ]    [ 0 0 ]
## Increment col 0:
## Before     After
## [ 0 0 ]    [ 1 0 ]
## [ 1 1 ]    [ 2 1 ]
## [ 0 0 ]    [ 1 0 ]
## [ 0 0 ]    [ 1 0 ]
##
## Apply [3,1]:
## Increment row 3:
## Before     After
## [ 1 0 ]    [ 1 0 ]
## [ 2 1 ]    [ 2 1 ]
## [ 1 0 ]    [ 1 0 ]
## [ 1 0 ]    [ 2 1 ]
## Increment col 1:
## Before     After
## [ 1 0 ]    [ 1 1 ]
## [ 2 1 ]    [ 2 2 ]
## [ 1 0 ]    [ 1 1 ]
## [ 2 1 ]    [ 2 2 ]
##
## Apply [2,0]:
## Increment row 2:
## Before     After
## [ 1 1 ]    [ 1 1 ]
## [ 2 2 ]    [ 2 2 ]
## [ 1 1 ]    [ 2 2 ]
## [ 2 2 ]    [ 2 2 ]
## Increment col 0:
## Before     After
## [ 1 1 ]    [ 2 1 ]
## [ 2 2 ]    [ 3 2 ]
## [ 2 2 ]    [ 3 2 ]
## [ 2 2 ]    [ 3 2 ]
##
## Apply [0,1]:
## Increment row 0:
## Before     After
## [ 2 1 ]    [ 3 2 ]
## [ 3 2 ]    [ 3 2 ]
## [ 3 2 ]    [ 3 2 ]
## [ 3 2 ]    [ 3 2 ]
## Increment col 1:
## Before     After
## [ 3 2 ]    [ 3 3 ]
## [ 3 2 ]    [ 3 3 ]
## [ 3 2 ]    [ 3 3 ]
## [ 3 2 ]    [ 3 3 ]
##
## Final:
## [ 3 3 ]
## [ 3 3 ]
## [ 3 3 ]
## [ 3 3 ]
#
############################################################
##
## discussion
##
############################################################
#
# First, we create the intial Matrix filled with 0's. Then we check
# each element of the @locations array: Add 1 to each element of the
# corresponding column and row. Then just walk the matrix once, counting
# the odd elements.
# 

use v5.36;

odd_matrix(2, 3, [0,1],[1,1]);
odd_matrix(2, 2, [1,1],[0,0]);
odd_matrix(3, 3, [0,0],[1,2],[2,1]);
odd_matrix(1, 5, [0,2],[0,4]);
odd_matrix(4, 2, [1,0],[3,1],[2,0],[0,1]);

sub odd_matrix($row, $col, @locations) {
    say "Input: $row, $col, (" . join(", ", map { "[$_->[0],$_->[1]]" } @locations), ")";
    my $matrix;
    foreach my $r (0..$row-1) {
        my $tmp = [];
        foreach my $c (0..$col-1) {
            push @$tmp, 0;
        }
        push @$matrix, $tmp;
    }
    foreach my $loc (@locations) {
        my ($r, $c) = @$loc;
        foreach my $col1 (0..scalar(@{$matrix->[0]})-1) {
            $matrix->[$r]->[$col1]++;
        }
        foreach my $row1 (0..scalar(@{$matrix})-1) {
            $matrix->[$row1]->[$c]++;
        }
    }
    my $output = 0;
    foreach my $r (0..$row-1) {
        foreach my $c (0..$col-1) {
            $output++ if $matrix->[$r]->[$c] % 2;
        }
    }
    say "Output: $output";
}