What this deck covers
This deck focuses on Implementing 2d Array Algorithms, giving you a quick way to review the definitions, rules, and examples that matter most for AP Computer Science a.
AP Computer Science a Flashcards: Implementing 2d Array Algorithms
Study Implementing 2d Array Algorithms in AP Computer Science a with focused flashcards that help you recognize the idea, recall the key rule, and apply it in practice-style prompts.
AP Computer Science a
Implementing 2d Array Algorithms
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Identify the method to access the element at row 2, column 3.
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ANSWER
array[2][3]. Uses bracket notation with row index first, then column index.
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Flashcard 1: Identify the method to access the element at row 2, column 3.
Answer: array[2][3]. Uses bracket notation with row index first, then column index.
Flashcard 2: What is the syntax to initialize a 2D array with specific values in Java?
Answer: int[][] array = {{1, 2, 3}, {4, 5, 6}};. Nested braces define rows and columns with literal values.
Flashcard 3: What is the syntax to declare a 2D array with predefined values?
Answer: int[][] array = {{1, 2}, {3, 4}};. Initializer lists create and populate array in one statement.
Flashcard 4: How do you declare a 2D array of integers in Java?
Answer: int[][] array;. Double brackets indicate two dimensions for row and column indices.
Flashcard 5: What is the syntax to copy a row of a 2D array?
Answer: Use System.arraycopy or a loop. Built-in method or manual iteration copies row elements.
Flashcard 6: Which option describes a jagged array?
Answer: Rows can have different lengths. Unlike rectangular arrays, each row can have different column count.
Flashcard 7: What does array[1] refer to in a 2D array?
Answer: The entire second row. Returns reference to the one-dimensional array at index 1.
Flashcard 8: What is the syntax to initialize a 2D array with specific values in Java?
Answer: int[][] array = {{1, 2, 3}, {4, 5, 6}};. Nested braces define rows and columns with literal values.
Flashcard 9: How do you pass a 2D array to a method in Java?
Answer: Use methodName(int[][] array). Parameter type specifies two-dimensional integer array reference.
Flashcard 10: What is the syntax to copy a row of a 2D array?
Answer: Use System.arraycopy or a loop. Built-in method or manual iteration copies row elements.
Flashcard 11: What is the key difference between 2D arrays and arrays of arrays?
Answer: Arrays of arrays can be jagged; 2D arrays are rectangular. Array of arrays allows variable row sizes, 2D arrays are fixed.
Flashcard 12: What is the time complexity to access an element in a 2D array?
Answer: O(1). Direct access by indices provides constant time complexity.
Flashcard 13: Find and correct the error: int[][] array = new int[][3];
Answer: Specify row size: new int[3][]. Row dimension must be specified first in array creation.
Flashcard 14: What is the key difference between 2D arrays and arrays of arrays?
Answer: Arrays of arrays can be jagged; 2D arrays are rectangular. Array of arrays allows variable row sizes, 2D arrays are fixed.
Flashcard 15: What is the result of accessing array[-1][0]?
Answer: ArrayIndexOutOfBoundsException. Negative indices are invalid and throw runtime exception.
Flashcard 16: What is the result of accessing array[-1][0]?
Answer: ArrayIndexOutOfBoundsException. Negative indices are invalid and throw runtime exception.
Flashcard 17: How do you pass a 2D array to a method in Java?
Answer: Use methodName(int[][] array). Parameter type specifies two-dimensional integer array reference.
Flashcard 18: Identify the method to sum all elements in a 2D array.
Answer: Use nested loops to iterate and sum elements. Accumulate values using nested iteration through all elements.
Flashcard 19: How do you set all elements in the first row to 0?
Answer: Use a loop: for (int i = 0; i < array[0].length; i++) array[0][i] = 0;. Loop through first row indices and assign zero values.
Flashcard 20: What is the best way to find the sum of a specific column?
Answer: Iterate over rows, sum the specific column. Access same column index across all rows and accumulate.
Flashcard 21: How do you iterate over all elements in a 2D array using nested loops?
Answer: Use two nested for loops. Outer loop for rows, inner loop for columns traverses all elements.
Flashcard 22: What is the result of array[0][5] if array has 4 columns?
Answer: ArrayIndexOutOfBoundsException. Index 5 exceeds valid column range, causing runtime error.
Flashcard 23: What is the output of array.length for int[][] array = new int[4][5]?
Answer:
Flashcard 24: Which option describes a jagged array?
Answer: Rows can have different lengths. Unlike rectangular arrays, each row can have different column count.
Flashcard 25: What is the index of the first row in a 2D array?
Answer:
Flashcard 26: What happens when you try to access array[0][10] in a 2D array?
Answer: ArrayIndexOutOfBoundsException. Index 10 exceeds array bounds, throwing runtime exception.
Flashcard 27: What is the consequence of not initializing a 2D array?
Answer: NullPointerException on access. Uninitialized array references are null, causing access errors.
Flashcard 28: Identify the method to access the element at row 2, column 3.
Answer: array[2][3]. Uses bracket notation with row index first, then column index.
Flashcard 29: What is the syntax to find the length of the second dimension?
Answer: array[0].length. Column count accessed through any row's length property.
Flashcard 30: How do you transpose a 2D array?
Answer: Swap rows with columns. Transform rows into columns and columns into rows.
Flashcard 31: What is the default value of int elements in a 2D array?
Answer:
Flashcard 32: How do you print all elements of a 2D array?
Answer: Use nested loops to iterate and print elements. Outer loop handles rows, inner loop handles columns for display.
Flashcard 33: What is the output of array.length for int[][] array = new int[4][5]?
Answer:
Flashcard 34: What is the consequence of not initializing a 2D array?
Answer: NullPointerException on access. Uninitialized array references are null, causing access errors.
Flashcard 35: How do you initialize a 2D array with 3 rows and 4 columns?
Answer: int[][] array = new int[3][4];. Creates array with specified row and column dimensions.
Flashcard 36: Find and correct the error: int[][] array = new int[][3];
Answer: Specify row size: new int[3][]. Row dimension must be specified first in array creation.
Flashcard 37: What is the correct way to compare two 2D arrays for equality?
Answer: Check length and compare each element. Verify dimensions match, then compare corresponding elements.
Flashcard 38: What is the length property of a 2D array in Java?
Answer: Number of rows (array.length). Returns the number of rows, not total elements.
Flashcard 39: What is the syntax to declare a 2D array with predefined values?
Answer: int[][] array = {{1, 2}, {3, 4}};. Initializer lists create and populate array in one statement.
Flashcard 40: Identify the method to sum all elements in a 2D array.
Answer: Use nested loops to iterate and sum elements. Accumulate values using nested iteration through all elements.
Flashcard 41: How do you set all elements in the first row to 0?
Answer: Use a loop: for (int i = 0; i < array[0].length; i++) array[0][i] = 0;. Loop through first row indices and assign zero values.
Flashcard 42: Identify the method to fill a 2D array with random values.
Answer: Use nested loops with Math.random(). Generate random numbers and assign to each array position.
Flashcard 43: Identify the method to find the maximum element in a 2D array.
Answer: Iterate and compare each element. Track maximum value while traversing all array elements.
Flashcard 44: Identify the method to find the maximum element in a 2D array.
Answer: Iterate and compare each element. Track maximum value while traversing all array elements.
Flashcard 45: How do you initialize a 2D array with 3 rows and 4 columns?
Answer: int[][] array = new int[3][4];. Creates array with specified row and column dimensions.
Flashcard 46: What is the result of array[0][5] if array has 4 columns?
Answer: ArrayIndexOutOfBoundsException. Index 5 exceeds valid column range, causing runtime error.
Flashcard 47: How can you set the element at row 1, column 2 to 5?
Answer: array[1][2] = 5;. Assignment operator sets value at specific row-column position.
Flashcard 48: What is a 2D array in Java?
Answer: A grid of elements stored in rows and columns. Arrays organized in row-column structure for storing tabular data.
Flashcard 49: What is the best way to find the sum of a specific column?
Answer: Iterate over rows, sum the specific column. Access same column index across all rows and accumulate.
Flashcard 50: How do you transpose a 2D array?
Answer: Swap rows with columns. Transform rows into columns and columns into rows.
Flashcard 51: What is the length property of a 2D array in Java?
Answer: Number of rows (array.length). Returns the number of rows, not total elements.
Flashcard 52: What is the default value of int elements in a 2D array?
Answer:
Flashcard 53: How do you declare a 2D array of integers in Java?
Answer: int[][] array;. Double brackets indicate two dimensions for row and column indices.
Flashcard 54: What is the index of the last column in a 2D array with 5 columns?
Answer:
Flashcard 55: What is the syntax to find the length of the second dimension?
Answer: array[0].length. Column count accessed through any row's length property.
Flashcard 56: What happens when you try to access array[0][10] in a 2D array?
Answer: ArrayIndexOutOfBoundsException. Index 10 exceeds array bounds, throwing runtime exception.
Flashcard 57: What does array[1] refer to in a 2D array?
Answer: The entire second row. Returns reference to the one-dimensional array at index 1.
Flashcard 58: How do you iterate over all elements in a 2D array using nested loops?
Answer: Use two nested for loops. Outer loop for rows, inner loop for columns traverses all elements.
Flashcard 59: How do you find the number of columns in the first row?
Answer: array[0].length. Access length property of any row to get column count.
Flashcard 60: How do you print all elements of a 2D array?
Answer: Use nested loops to iterate and print elements. Outer loop handles rows, inner loop handles columns for display.
Flashcard 61: How can you set the element at row 1, column 2 to 5?
Answer: array[1][2] = 5;. Assignment operator sets value at specific row-column position.
Flashcard 62: What is the index of the last column in a 2D array with 5 columns?
Answer:
Flashcard 63: What is the time complexity to access an element in a 2D array?
Answer: O(1). Direct access by indices provides constant time complexity.
Flashcard 64: Identify the method to fill a 2D array with random values.
Answer: Use nested loops with Math.random(). Generate random numbers and assign to each array position.
Flashcard 65: What is the index of the first row in a 2D array?
Answer:
Flashcard 66: What is the purpose of array[0].length in a 2D array?
Answer: To get the number of columns in the first row. Determines column count for the first row dimension.
Flashcard 67: What is a 2D array in Java?
Answer: A grid of elements stored in rows and columns. Arrays organized in row-column structure for storing tabular data.
Flashcard 68: What is the purpose of array[0].length in a 2D array?
Answer: To get the number of columns in the first row. Determines column count for the first row dimension.
Flashcard 69: What is the correct way to compare two 2D arrays for equality?
Answer: Check length and compare each element. Verify dimensions match, then compare corresponding elements.
Flashcard 70: How do you find the number of columns in the first row?
Answer: array[0].length. Access length property of any row to get column count.