TOPIC 5: Assignment Answers

[alyeffy]

Here are the answers for the homework assignments for Topic 5. Please let me know if you have any questions/concerns about them!

Algorithms (Basic Version pp 206 - 209) Review Questions
NOTE: The following solutions for these review questions might not be the be-all and end-all. If you think your solution might be correct, let me know and I can take a look for you.

1. Replace all the highs and lows.

public int[] replaceHighAndLow(int[] arr) {
    int[] tempArrray = new int[arr.length];

    for (int i = 0; i < arr.length; i++;) {
        if (arr[i] > 750) {
            tempArray[i] = 1000;
        } else if (arr[i] < 250) {
            tempArray[i] = 0;
        } else {
            tempArray[i] = arr[i];
        }
    }
    return tempArray;
}

2. Determine if the numbers in an ArrayList are always increasing.

private static boolean isIncreasing(ArrayList<Integer> arr) {
    for (int i = 1; i < arr.size(); i++) {
        if (arr.get(i) <= arr.get(i - 1))
            return false;
    }
    return true;
}

3. Find all the songs that contain the world "Love" in the title.

private static int findCount(String[][] arr, String target) {
    int count = 0;
    for (int r = 0; r < arr.length; r++) {
        for (int c = 0; c < arr[r].length; c++) {
            if (arr[r][c].indexOf(target) != -1)
                count++;
         }
    }
    return count;
}

4. Determine the relative strength index of a stock.

public int[] overpriced(double[] rsiValues) {
    int[] temp = new int[rsiValues.length];
    for (int i = 0; i < rsiValues.length; i++) {
        if (rsiValues[i] >= 70 )
            temp[i] = 1;
        else
            temp[i] = 0;
    }
    return temp;
}

5. Fill an array with random chosen even numbers.

public int[] onlyEvens(int arraySize, int range) {
    int[] evens = new int[arraySize];

    for (int i = 0; i < arraySize; i++) {
        int number = (int) (Math.random() * range);
        while (number % 2 != 0) {
            number = (int) (Math.random() * range);
        }
        evens[i] = number;
    }
    return evens;
}

6. Determine if the rate is increasing.

private static boolean rateIsIncreasing(ArrayList<Double> stockPrices) {
    for (int i = 2; i < stockPrices.size(); i++) {
        if ((stockPrices.get(i) - stockPrices.get(i-1)) <= (stockPrices.get(i-1) - stockPrices.get(i-2)))
            return false;
    }
    return true;
}

Sorting and Searching Question Set

Q	A
1	E
2	D
3	C
4	B
5	C
6	E
7	C
8	A
9	A
10	C
11	B
12	D
13	A
14	E
15	A
16	B
17	B
18	A
19	D
20	A
21	E
22	C
23	D
24	C
25	E
26	D
27	D
28	B
29	B
30	B
31	A
32	D
33	E
34	D
35	A
36	C