Merge pull request #12940 from pme/challenge-345

challenge-345

4 files changed, 362 insertions, 0 deletions

diff --git a/challenge-345/peter-meszaros/perl/ch-1.pl b/challenge-345/peter-meszaros/perl/ch-1.pl
new file mode 100755
index 0000000000..8d051a87c2
--- /dev/null
+++ b/challenge-345/peter-meszaros/perl/ch-1.pl
@@ -0,0 +1,78 @@
+#!/usr/bin/env perl
+#
+=head1 Task 1: Peak Positions
+
+Submitted by: Mohammad Sajid Anwar
+
+You are given an array of integers, @ints.
+
+Find all the peaks in the array, a peak is an element that is strictly greater
+than its left and right neighbours. Return the indices of all such peak
+positions.
+
+=head2 Example 1
+
+    Input: @ints = (1, 3, 2)
+    Output: (1)
+
+=head2 Example 2
+
+    Input: @ints = (2, 4, 6, 5, 3)
+    Output: (2)
+
+=head2 Example 3
+
+    Input: @ints = (1, 2, 3, 2, 4, 1)
+    Output: (2, 4)
+
+=head2 Example 4
+
+    Input: @ints = (5, 3, 1)
+    Output: (0)
+
+=head2 Example 5
+
+    Input: @ints = (1, 5, 1, 5, 1, 5, 1)
+    Output: (1, 3, 5)
+
+=cut
+
+use strict;
+use warnings;
+use Test2::V0 -no_srand => 1;
+use Data::Dumper;
+use constant { true => 1, false => 0 };
+
+my $cases = [
+    [[1, 3, 2],             [1],       "Example 1"],
+    [[2, 4, 6, 5, 3],       [2],       "Example 2"],
+    [[1, 2, 3, 2, 4, 1],    [2, 4],    "Example 3"],
+    [[5, 3, 1],             [0],       "Example 4"],
+    [[1, 5, 1, 5, 1, 5, 1], [1, 3, 5], "Example 5"],
+];
+
+sub peak_positions
+{
+    my $ints = shift;
+
+    my @peaks;
+    my $len = @$ints;
+    for (my $i = 0; $i < $len; $i++) {
+        if ($i == 0) {
+            push @peaks, $i if $ints->[$i] > $ints->[$i + 1];
+        } elsif ($i == $len - 1) {
+            push @peaks, $i if $ints->[$i] > $ints->[$i - 1];
+        } else {
+            push @peaks, $i if $ints->[$i] > $ints->[$i - 1]
+                            && $ints->[$i] > $ints->[$i + 1];
+        }
+    }
+    return \@peaks;
+}
+
+for (@$cases) {
+    is(peak_positions($_->[0]), $_->[1], $_->[2]);
+}
+done_testing();
+
+exit 0;
diff --git a/challenge-345/peter-meszaros/perl/ch-2.pl b/challenge-345/peter-meszaros/perl/ch-2.pl
new file mode 100755
index 0000000000..e3144a498c
--- /dev/null
+++ b/challenge-345/peter-meszaros/perl/ch-2.pl
@@ -0,0 +1,102 @@
+#!/usr/bin/env perl
+#
+=head1 Task 2: Last Visitor
+
+Submitted by: Mohammad Sajid Anwar
+
+You are given an integer array @ints where each element is either a positive
+integer or -1.
+
+We process the array from left to right while maintaining two lists:
+
+    @seen: stores previously seen positive integers (newest at the front)
+    @ans: stores the answers for each -1
+
+Rules:
+
+    If $ints[i] is a positive number -> insert it at the front of @seen
+    If $ints[i] is -1:
+
+        Let $x be how many -1s in a row we've seen before this one.
+
+        If $x < len(@seen) -> append seen[x] to @ans
+
+        Else -> append -1 to @ans
+
+        At the end, return @ans.
+
+=head2 Example 1
+
+    Input: @ints = (5, -1, -1)
+    Output: (5, -1)
+
+    @seen = (5)
+    First  -1: @ans = (5)
+    Second -1: @ans = (5, -1)
+
+=head2 Example 2
+
+    Input: @ints = (3, 7, -1, -1, -1)
+    Output: (7, 3, -1)
+
+    @seen = (3, 7)
+    First  -1: @ans = (7)
+    Second -1: @ans = (7, 3)
+    Third  -1: @ans = (7, 3, -1)
+
+=head2 Example 3
+
+    Input: @ints = (2, -1, 4, -1, -1)
+    Output: (2, 4, 2)
+
+=head2 Example 4
+
+    Input: @ints = (10, 20, -1, 30, -1, -1)
+    Output: (20, 30, 20)
+
+=head2 Example 5
+
+    Input: @ints = (-1, -1, 5, -1)
+    Output: (-1, -1, 5)
+
+=cut
+
+use strict;
+use warnings;
+use Test2::V0 -no_srand => 1;
+use Data::Dumper;
+use constant { true => 1, false => 0 };
+
+my $cases = [
+    [[ 5, -1, -1],             [5, -1],      "Example 1"],
+    [[ 3,  7, -1, -1, -1],     [7, 3, -1],   "Example 2"],
+    [[ 2, -1,  4, -1, -1],     [2, 4, 2],    "Example 3"],
+    [[10, 20, -1, 30, -1, -1], [20, 30, 20], "Example 4"],
+    [[-1, -1,  5, -1],         [-1, -1, 5],  "Example 5"],
+];
+
+sub last_visitor
+{
+    my $ints = shift;
+
+    my @seen;
+    my @ans;
+    my $minus_count = 0;
+    for my $i (@$ints) {
+        if ($i == -1) {
+            push @ans, $minus_count < @seen ? $seen[$minus_count] : -1;
+            $minus_count++;
+        } else {
+            unshift @seen, $i;
+            $minus_count = 0;
+        }
+    }
+    return \@ans;
+}
+
+for (@$cases) {
+    is(last_visitor($_->[0]), $_->[1], $_->[2]);
+}
+done_testing();
+
+exit 0;
diff --git a/challenge-345/peter-meszaros/tcl/ch-1.tcl b/challenge-345/peter-meszaros/tcl/ch-1.tcl
new file mode 100755
index 0000000000..2c7b3f27e2
--- /dev/null
+++ b/challenge-345/peter-meszaros/tcl/ch-1.tcl
@@ -0,0 +1,80 @@
+#!/usr/bin/env tclsh
+#
+# Task 1: Peak Positions
+# 
+# Submitted by: Mohammad Sajid Anwar
+# 
+# You are given an array of integers, @ints.
+# 
+# Find all the peaks in the array, a peak is an element that is strictly greater
+# than its left and right neighbours. Return the indices of all such peak
+# positions.
+# 
+# Example 1
+# 
+#     Input: @ints = (1, 3, 2)
+#     Output: (1)
+# 
+# Example 2
+# 
+#     Input: @ints = (2, 4, 6, 5, 3)
+#     Output: (2)
+# 
+# Example 3
+# 
+#     Input: @ints = (1, 2, 3, 2, 4, 1)
+#     Output: (2, 4)
+# 
+# Example 4
+# 
+#     Input: @ints = (5, 3, 1)
+#     Output: (0)
+# 
+# Example 5
+# 
+#     Input: @ints = (1, 5, 1, 5, 1, 5, 1)
+#     Output: (1, 3, 5)
+# 
+
+package require tcltest
+
+set cases {
+    {{1 3 2}             {1} "Example 1"}
+    {{2 4 6 5 3}         {2} "Example 2"}
+    {{1 2 3 2 4 1}     {2 4} "Example 3"}
+    {{5 3 1}             {0} "Example 4"}
+    {{1 5 1 5 1 5 1} {1 3 5} "Example 5"}
+}
+
+proc peak_positions {ints} {
+    set peaks {}
+    set len [llength $ints]
+    for {set i 0} {$i < $len} {incr i} {
+        if {$i == 0} {
+            if {[lindex $ints $i] > [lindex $ints [expr $i + 1]]} {
+                lappend peaks $i
+            }
+        } elseif {$i == [expr {$len - 1}]} {
+            if {[lindex $ints $i] > [lindex $ints [expr $i - 1]]} {
+                lappend peaks $i
+            }
+        } else {
+            if {[lindex $ints $i] > [lindex $ints [expr $i - 1]] &&
+                [lindex $ints $i] > [lindex $ints [expr $i + 1]]} {
+                lappend peaks $i
+            }
+        }
+    }
+    return $peaks
+
+}
+
+tcltest::configure -verbose {pass}
+foreach case $cases {
+    tcltest::test [lindex $case 2] {} {
+        peak_positions [lindex $case 0]
+    } [lindex $case 1]
+}
+
+exit 0
+
diff --git a/challenge-345/peter-meszaros/tcl/ch-2.tcl b/challenge-345/peter-meszaros/tcl/ch-2.tcl
new file mode 100755
index 0000000000..4a5d998cf8
--- /dev/null
+++ b/challenge-345/peter-meszaros/tcl/ch-2.tcl
@@ -0,0 +1,102 @@
+#!/usr/bin/env tclsh
+#
+# Task 2: Last Visitor
+# 
+# Submitted by: Mohammad Sajid Anwar
+# 
+# You are given an integer array @ints where each element is either a positive
+# integer or -1.
+# 
+# We process the array from left to right while maintaining two lists:
+# 
+#     @seen: stores previously seen positive integers (newest at the front)
+#     @ans: stores the answers for each -1
+# 
+# Rules:
+# 
+#     If $ints[i] is a positive number -> insert it at the front of @seen
+#     If $ints[i] is -1:
+# 
+#         Let $x be how many -1s in a row we've seen before this one.
+# 
+#         If $x < len(@seen) -> append seen[x] to @ans
+# 
+#         Else -> append -1 to @ans
+# 
+#         At the end, return @ans.
+# 
+# Example 1
+# 
+#     Input: @ints = (5, -1, -1)
+#     Output: (5, -1)
+# 
+#     @seen = (5)
+#     First  -1: @ans = (5)
+#     Second -1: @ans = (5, -1)
+# 
+# Example 2
+# 
+#     Input: @ints = (3, 7, -1, -1, -1)
+#     Output: (7, 3, -1)
+# 
+#     @seen = (3, 7)
+#     First  -1: @ans = (7)
+#     Second -1: @ans = (7, 3)
+#     Third  -1: @ans = (7, 3, -1)
+# 
+# Example 3
+# 
+#     Input: @ints = (2, -1, 4, -1, -1)
+#     Output: (2, 4, 2)
+# 
+# Example 4
+# 
+#     Input: @ints = (10, 20, -1, 30, -1, -1)
+#     Output: (20, 30, 20)
+# 
+# Example 5
+# 
+#     Input: @ints = (-1, -1, 5, -1)
+#     Output: (-1, -1, 5)
+# 
+
+package require tcltest
+
+set cases {
+    {{ 5 -1 -1}          {5 -1}     "Example 1"}
+    {{ 3  7 -1 -1 -1}    {7 3 -1}   "Example 2"}
+    {{ 2 -1  4 -1 -1}    {2 4 2}    "Example 3"}
+    {{10 20 -1 30 -1 -1} {20 30 20} "Example 4"}
+    {{-1 -1  5 -1}       {-1 -1 5}  "Example 5"}
+}
+
+proc last_visitor {ints} {
+    set seen {}
+    set ans {}
+    set minus_count 0
+    foreach i $ints {
+        if {$i == -1} {
+            if {$minus_count < [llength $seen]} {
+                lappend ans [lindex $seen $minus_count]
+            } else {
+                lappend ans -1
+            }
+            incr minus_count
+        } else {
+            set seen [linsert $seen 0 $i]
+            set minus_count 0
+        }
+    }
+    return $ans
+
+}
+
+tcltest::configure -verbose {pass}
+foreach case $cases {
+    tcltest::test [lindex $case 2] {} {
+        last_visitor [lindex $case 0]
+    } [lindex $case 1]
+}
+
+exit 0
+