Module 3 - Technical - Web Unit 4 Sprint 16 ACS 3

Advanced Algorithms

Mastering Complex Algorithms

In this module, you'll focus on more complex algorithmic techniques that are frequently assessed in technical interviews and essential for performance optimization.

Key Points:

  • Analyze time and space complexity accurately
  • Recognize patterns in advanced problems
  • Apply appropriate data structures for optimization
  • Implement efficient solutions for complex scenarios

Advanced Algorithm Patterns:

This module covers these critical advanced patterns:

  • Dynamic Programming - Breaking complex problems into simpler overlapping subproblems
  • Graph Algorithms - Solving traversal, shortest path, and connectivity problems
  • Backtracking - Finding all (or some) solutions to computational problems

Example of a Dynamic Programming solution:

// Fibonacci sequence using dynamic programming
function fibonacci(n) {
    // Base cases
    if (n <= 1) return n;
    
    // Create array to store already calculated values
    const dp = new Array(n + 1);
    dp[0] = 0;
    dp[1] = 1;
    
    // Build up from smaller subproblems
    for (let i = 2; i <= n; i++) {
        dp[i] = dp[i - 1] + dp[i - 2];
    }
    
    return dp[n];
}

// O(n) time complexity vs O(2^n) with naive recursive approach
console.log(fibonacci(10)); // Output: 55

Practice GCA Test

Take the Practice GCA

Regular practice with the General Code Assessment (GCA) is essential for achieving a high score. The more comfortable you become with the test format and types of problems, the better your chances of success.

  1. Go to Practice GCA Test
  2. Select your preferred programming language
  3. Agree to the Terms and Pledges
  4. Click Start to begin the test
  5. Complete all tasks to the best of your ability
  6. Click "Finish My Session" when done

Advanced Practice Tips

  • Take practice tests regularly to build familiarity
  • Review your solutions and learn from mistakes
  • Focus on improving your score with each attempt
  • Timed practice helps develop speed and accuracy
  • Analyze edge cases in your solutions to prevent common bugs
  • After each test, identify your weak areas and focus on those topics

Take the Official GCA

Ready for the Real Test?

Now that you've practiced extensively, it's time to take the official GCA test. Remember that you can only take the official test every two weeks, so prepare thoroughly before attempting.

Before You Begin:

  • Have a government-issued photo ID ready
  • Ensure you have a reliable internet connection
  • Find a quiet space with minimal distractions
  • Reserve 1 hour and 10 minutes for the test
  • Use Chrome or Firefox browser
  • Make sure your webcam and microphone are working

Once you're ready, click the button below to start the official GCA:

Take Official GCA

Code-Along Sessions

Available Sessions

Arrays and Moving Windows

Starter Code Solution

Big O Analysis and Caching

Starter Code Solution
Schedule a Code-Along

Additional Resources

LeetCode Advanced Collections

The CodeSignal Arcade is no longer available. Instead, we recommend LeetCode's advanced problem collections to strengthen your problem-solving skills:

Example of a graph algorithm (BFS approach):

// Number of Islands - BFS Approach
// Count the number of islands in a 2D grid

function numIslands(grid) {
    if (!grid || grid.length === 0) return 0;
    
    const rows = grid.length;
    const cols = grid[0].length;
    let count = 0;
    
    for (let r = 0; r < rows; r++) {
        for (let c = 0; c < cols; c++) {
            if (grid[r][c] === '1') {
                count++;
                // Use BFS to mark all connected land as visited
                bfs(grid, r, c, rows, cols);
            }
        }
    }
    
    return count;
}

function bfs(grid, r, c, rows, cols) {
    const queue = [[r, c]];
    grid[r][c] = '0'; // Mark as visited
    
    // Define directions: up, right, down, left
    const dirs = [[-1, 0], [0, 1], [1, 0], [0, -1]];
    
    while (queue.length > 0) {
        const [row, col] = queue.shift();
        
        // Check all 4 directions
        for (const [dr, dc] of dirs) {
            const newRow = row + dr;
            const newCol = col + dc;
            
            // Check bounds and if it's land
            if (newRow >= 0 && newRow < rows && 
                newCol >= 0 && newCol < cols && 
                grid[newRow][newCol] === '1') {
                grid[newRow][newCol] = '0'; // Mark as visited
                queue.push([newRow, newCol]);
            }
        }
    }
}

Code-Along Preparation

This comprehensive preparation guide will help you get the most out of the advanced code-along sessions in this module.