Liban & Stephen project done#7
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auberonedu
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auberonedu
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Nice job! However, there are a few places where the complexity analysis is off and your space efficient solution does not meet the O(1) space requirement. Consider taking another look at these.
| // Time Complexity: O(n^2) | ||
| // Space Complexity: O(1) | ||
| public static int sumDiagonal(int[][] matrix){ | ||
| int sum = 0; | ||
| for (int i = 0; i < matrix.length; i++) { | ||
| sum += matrix[i][i]; |
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Take another look at the time complexity here. How many times does the for loop run?
| * Time Complexity: O(n) | ||
| * Space Complexity: O(1) | ||
| * | ||
| * @param nums An array of integers | ||
| * @return the integer that shows up most commonly | ||
| */ | ||
| public static int mostCommonTimeEfficient(int[] nums) { | ||
| // TODO: Complete this method with an implementation that runs | ||
| // in O(n) time. n = nums.size() | ||
| return -1; | ||
| int highestValue = 0; | ||
| Map <Integer, Integer> mostCommon = new HashMap<Integer, Integer>(); |
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Take another look at the space complexity. Think of what data structures you're allocating, and how they'll grow as the input size increases.
| * Space Complexity: O(1) | ||
| * | ||
| * @param nums An array of integers | ||
| * @return the integer that shows up most commonly | ||
| */ | ||
| public static int mostCommonSpaceEfficient(int[] nums) { | ||
| // TODO: Complete this method with an implementation that runs | ||
| // in O(1) space. | ||
| return -1; | ||
| int highestCommon = 0; | ||
| int mostFrequentNum = nums[0];; | ||
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| Map <Integer, Integer> mostCommon = new HashMap<Integer, Integer>(); |
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Again, take a look at the space complexity. This doesn't satisfy the requirement of O(1) space.
| int[] numsTest = new int[6]; | ||
| numsTest[0] = 1; | ||
| numsTest[1] = 6; | ||
| numsTest[2] = 2; | ||
| numsTest[3] = 4; | ||
| numsTest[4] = 2; | ||
| numsTest[5] = 2; |
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Consider using a shorter syntax to initialize arrays:
int[] numsTest = {1, 6, 2, 4, 2, 2};
| @Test | ||
| void testMostCommonSpaceEfficient(){ | ||
| int[] numsTest = {1, 2, 3, 3, 4, 4, 2}; | ||
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| int howMany = Practice.mostCommonSpaceEfficient(numsTest); | ||
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| assertEquals( 2, howMany); | ||
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| } |
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These are good tests, but we need more of them to have more confidence that our solution is working. What other cases can you test?
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