Recap: Simple Grid Exercise

Part of the Logic & Flow section of Coddy's PHP journey — lesson 32 of 68.

Challenge

Easy

You will receive one input: a 2D array representing a simple game grid in JSON format. The grid contains numbers representing different tile values. Read the input, convert the JSON string to a 2D array, and perform the following operations:

Calculate and print the sum of all values in the grid
Find and print the maximum value in the grid
Count and print how many tiles have a value greater than 5
Print the value located at row 1, column 2 (using 0-based indexing)

Print each result on a separate line in the exact order specified above.

Input format: One line containing a JSON array representing the game grid (example: [[3,7,2],[5,9,1],[8,4,6]])

Expected output:

Line 1: Sum of all values
Line 2: Maximum value
Line 3: Count of tiles with value greater than 5
Line 4: Value at row 1, column 2

Try it yourself

<?php
// Read the JSON input
$input = trim(fgets(STDIN));

// Convert JSON string to 2D array
// Important: Use (array) to ensure proper array conversion
$grid = json_decode($input, true);

// TODO: Write your code below
// 1. Calculate the sum of all values in the grid
// 2. Find the maximum value in the grid
// 3. Count how many tiles have a value greater than 5
// 4. Get the value at row 1, column 2

// Output the results (one per line)
// echo $sum . "\n";
// echo $max . "\n";
// echo $count . "\n";
// echo $value . "\n";
?>

All lessons in Logic & Flow

1Advanced Functions

Anonymous Functions Closures and 'use'Arrow Functions Callback Functions Using 'call_user_func'Variable Functions Passing by Reference Recursive Functions Recap: Function Medley

4Multi-dimensional Arrays

Creating a 2D Array Accessing 2D Array Elements Modifying 2D Array Elements Iterating with Nested Loops 2D Associative ArraysRecap: Simple Grid Exercise

7Working with Dates and Times

The 'date()' Function Unix Timestamps with 'time()'Intro to the DateTime Object Formatting DateTime Objects Modifying DateTime Objects Recap: Date Calculations

10Final Challenges

Challenge: Palindrome Checker Challenge: Character Frequency Challenge: Shopping Cart Total Challenge: Unique Item Filter