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Write the simulateOneDay method, which simulates numBirds birds or possibly a bear at the bird feeder for one day. The method determines the amount of food taken from the feeder on this day and updates the currentFood instance variable. The simulation accounts for normal conditions, which occur 95% of the time, and abnormal conditions, which occur the other 5% of the time.

Under normal conditions, the simulation assumes that on any given day, only birds visit the feeder and that each bird at the feeder consumes the same amount of food. This standard amount consumed is between 10 and 50 grams of food, inclusive, in 1-gram increments. That is, on any given day, each bird might eat 10, 11, . . . , 49, or 50 grams of food. The amount of food eaten by each bird on a given day is randomly generated and each integer from 10 to 50, inclusive, has an equal chance of being chosen.

For example, a run of the simulation might predict that for a certain day under normal conditions, each bird coming to the feeder will eat 11 grams of food. If 10 birds come to the feeder on that day, then a total of 110 grams of food will be consumed.

If the simulated food consumed is greater than the amount of food in the feeder at the beginning of the day, the simulation empties the feeder and the amount of food in the feeder at the end of the day is zero.

Under abnormal conditions, a bear empties the feeder and the amount of food in the feeder at the end of the day is zero.

The following examples show possible results of three calls to simulateOneDay.

• Example 1: If the feeder initially contains 500 grams of food, the call simulateOneDay(12) could result in 12 birds eating 20 grams of food each, leaving 260 grams of food in the feeder.
• Example 2: If the feeder initially contains 1,000 grams of food, the call simulateOneDay(22) could result in a bear eating all the food, leaving 0 grams of food in the feeder.
• Example 3: If the feeder initially contains 100 grams of food, the call simulateOneDay(5) could result in 5 birds attempting to eat 30 grams of food each. Since the feeder initially contains less than 150 grams of food, the feeder is emptied, leaving 0 grams of food in the feeder.

Complete the simulateOneDay method.

/**
 * Simulates one day with numBirds birds or possibly a bear at the bird feeder,
 * as described in part (a)
 * Precondition: numBirds > 0
 */
public void simulateOneDay(int numBirds)

Class information for this question

public class Feeder
private int currentFood
public void simulateOneDay(int numBirds)
public int simulateManyDays(int numBirds, int numDays)

Write the simulateManyDays method. The method uses simulateOneDay to simulate the feeder on at most numDays consecutive days. The numBirds birds or a bear coming to the feeder on each day of the simulation returns the number of days that birds or a bear found food at the feeder.

Consider the following examples.

Complete the simulateManyDays method. Assume that simulateOneDay works as intended, regardless of what you wrote in part (a). You must use simulateOneDay appropriately in order to receive full credit.

/**
 * Returns the number of days birds or a bear found food to eat at the feeder in this simulation,
 * as described in part (b)
 * Precondition: numBirds > 0, numDays > 0
 */
public int simulateManyDays(int numBirds, int numDays)

Class information for this question

public class Feeder
private int currentFood
public void simulateOneDay(int numBirds)
public int simulateManyDays(int numBirds, int numDays)

Write the isWordChain method, which determines whether each element of wordList (except the first) contains the previous element as a substring. The following table shows two sample isWordChain method calls.

Complete the isWordChain method.

/**
 * Returns true if each element of wordList (except the first) contains the previous
 * element as a substring and returns false otherwise, as described in part (a)
 * Precondition: wordList contains at least two elements.
 * Postcondition: wordList is unchanged.
 */
public boolean isWordChain()

Write the createList method, which creates and returns an ArrayList<String>. The method identifies strings in wordList that start with target and returns a new ArrayList containing each identified string without the starting occurrence of target. Elements must appear in the returned list in the same order as they appear in wordList.

Consider an example where wordList contains the following strings.

["catch", "bobcat", "catchacat", "cat", "at"]

The following table shows the ArrayList returned by some calls to createList. In all cases, wordList is unchanged.

Complete the createList method.

/**
 * Returns an ArrayList<String> based on strings from wordList that start
 * with target, as described in part (b). Each element of the returned ArrayList has had
 * the initial occurrence of target removed.
 * Postconditions: wordList is unchanged.
 *      Items appear in the returned list in the same order as they appear in wordList.
 */
public ArrayList<String> createList(String target)

Class information for this question

public class WordChecker
private ArrayList<String> wordList

public boolean isWordChain()
public ArrayList<String> createList(String target)

Write the getNextLoc method, which returns a Location object that represents the smaller of two neighbors of the grid element at row and col, according to the following rules.

• The two neighbors that are considered as the element below the given element and the element to the right of the given element, if they exist.
• If both neighbors exist, the Location of the neighbor with the smaller value is returned. Two neighbors will always have different values.
• If only one neighbor exists, the Location of the existing neighbor is returned.

For example, assume that grid contains the following values.

The following table shows some sample calls to getNextLoc.

In the example, the getNextLoc method will never be called with row 4 and column 4, as those values would violate the precondition of the method.

Complete the getNextLoc method.

/**
 * Returns the Location representing a neighbor of the grid element at row and col,
 * as described in part (a)
 * Preconditions: row is a valid row index and col is a valid column index in grid.
 *      row and col do not specify the element in the last row and last column of grid.
 */
public Location getNextLoc(int row, int col)

Class information for this question

public class Location
private int theRow
private int theCol

public Location(int r, int c)
public int getRow()
public int getCol()

public class GridPath
private int[][] grid

public Location getNextLoc(int row, int col)
public int sumPath(int row, int col)

Write the sumPath method, which returns the sum of all values on a path in grid. The path begins with the element at row and col and is determined by successive calls to getNextLoc. The path ends when the element in the last row and last column of grid is reached.

For example, consider the following contents of grid. The shaded elements of grid represent the values on the path that results from the method call sumPath(1, 1). The method call returns 19 because $3 + 2 + 9 + 4 + 0 + 1 = 19$.

[Grid diagram: 4x5 table of integers, rows 0-3 and columns 0-4 labelled. The shaded (bolded) path cells forming the path from sumPath(1,1) are: (1,1)=3, (2,1)=2, (2,2)=9, (2,3)=4, (2,4)=0, (3,4)=1, matching the sum $3+2+9+4+0+1=19$.]

Write the sumPath method. Assume getNextLoc works as intended, regardless of what you wrote in part (a). You must use getNextLoc appropriately in order to receive full credit.

/**
 * Computes and returns the sum of all values on a path through grid, as described in
 * part (b)
 * Preconditions: row is a valid row index and col is a valid column index in grid.
 *      row and col do not specify the element in the last row and last column of grid.
 */
public int sumPath(int row, int col)

Class information for this question

public class Location
private int theRow
private int theCol

public Location(int r, int c)
public int getRow()
public int getCol()

public class GridPath
private int[][] grid

public Location getNextLoc(int row, int col)
public int sumPath(int row, int col)