Solving with Ruby, Perl, Java and Python AtCoder ABC 131 D Array Sorting

Introduction

• AtCoder Problems * Use Recommendations to solve past problems. Thanks to AtCoder and AtCoder Problems.

This theme

AtCoder Beginner Contest 131 D - Megalomania Difficulty: 594

This theme, sorting of arrays Ruby It's an array sort, so I think it's easy to implement. ~~ I chose a lighter question because it's my first Python. ~~

ruby.rb

n = gets.to_i
a = Array.new(n){gets.split.map(&:to_i)}
a.sort_by!{|x| x[1]}
ans = 0
n.times do |i|
  ans += a[i][0]
  if ans > a[i][1]
    puts "No"
    exit
  end
end
puts "Yes"

sort.rb

a.sort_by!{|x| x[1]}

~~ Sorting is done by multiple conditions, but for learning purposes, only one can be sorted as a solution. ~~ ** Addition ** Some corrections have been made from the comments received. Python It is almost a sutra copy because it is solved with *** Python *** for the first time.

python.py

n = int(input())
a = list(list(map(int, input().split())) for _ in range(n))
a.sort(key=lambda x: x[1])
ans = 0
for i in range(0, n):
    ans += a[i][0]
    if ans > a[i][1]:
        print("No")
        exit()
print("Yes")

Coding is easy because the VSCode extension is working.

range.py

for i in range(0, n):
for i in range(0, n - 1):

I tried to turn it with i at for, but I wrote n -1 and got WA.

Next time, I will try to sort by multiple conditions. Perl

perl.pl

chomp (my $n = <STDIN>);
my @a;
for my $i (0..$n-1) {
  my @in = split / /, <STDIN>;
  ($a[$i][0], $a[$i][1]) = @in;
}
@a = sort {$$a[1]<=>$$b[1] || $$b[0]<=>$$a[0]} @a;

my $ans = 0;
for my $i (0..$n-1) {
  $ans += $a[$i][0];
  if ($ans>$a[$i][1]) {
    print "No\n";
    exit;
  }
}
print "Yes\n";

sort.pl

@a = sort {$$a[1]<=>$$b[1] || $$b[0]<=>$$a[0]} @a;

• Perl * is a multi-condition sort. Java

java.java

import java.util.*;

class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = Integer.parseInt(sc.next());
        List<Work> work = new ArrayList<>();
        for (int i = 0; i < n; i++) {
            int time = Integer.parseInt(sc.next());
            int limit = Integer.parseInt(sc.next());
            work.add(new Work(time, limit));
        }
        sc.close();
        work.sort(Comparator.comparingInt(x -> x.limit));
        int ans = 0;
        for (int i = 0; i < n; i++) {
            ans += work.get(i).time;
            if (ans > work.get(i).limit) {
                System.out.println("No");
                return;
            }
        }
        System.out.println("Yes");
    }

    static class Work {
        int time;
        int limit;

        Work(int time, int limit) {
            this.time = time;
            this.limit = limit;
        }
    }
}

sort.java

        work.sort(Comparator.comparingInt(x -> x.limit));

• Java * is a singular sort.

** Addition ** As I was told in the comments, I changed the sort comparison part to code that uses the Comparator introduced in java8. Safer and slightly faster.

Summary

• Solved ABC 131 D
• Become familiar with Ruby
• Become familiar with Python
• Become familiar with Perl
• Become familiar with Java