排序比较计数器
我有这个代码对一个填充了随机数的数组进行排序，并计算完成排序所需的数字比较。 我正在使用排序方法选择气泡和合并排序。 我有选择和泡沫的计数器，但没有合并我不知道在哪里放它。 这可能是一个简单的答案，但我无法让它工作。
码：
/*********************************************************************** * * Selection Sort: * Reads in the array and then searches for the largest number. * After it finds the largest number, it then swaps that number with the * last number of the array * Precondition: takes in an array of "n" items, which in this particular * case is 2000, 4000, 6000, 8000, and 10000 random items in an array * Postcondition: all numbers are sorted in ascending order * **********************************************************************/ public static int SelectionSort (int[] intArray) { //Set initial count of comparisons at 0 comparisons= 0; //Number of swaps made for(int last = intArray.length - 1; last > 0; last--) { int largestIndex = last; //Int which places the largest number at the end of the array // Find largest number for(int i = 0; i the last number if (intArray[i] > intArray[largestIndex]){ largestIndex = i; //switch the last number and i } // end if //Comparison+1 comparisons++; } // end for // Swap last element with largest element int largest = intArray[last]; intArray[last] = intArray[largestIndex]; intArray[largestIndex] = largest; } //Return comparison counter return comparisons; } /*********************************************************************** * * Bubble Sort: * Takes an array of random integers and sorts them by comparing adjacent * numbers to one another. Whichever the larger adjacent number, Bubble * Sort switches it towards the back end of the adjacent numbers. It does * this until the list is fully sorted. * Precondition: takes in a random array of integers * Postcondition: array is sorted from smallest to largest * **********************************************************************/ public static int BubbleSort (int[] intArray) { //Instance Variables int n = intArray.length; //boolean swap; comparisons = 0; //swap = false; //for i starts at 0, when i is less than array length, i++ until reach array length for(int i=0; i < n; i++) { for(int j=1; j intArray[j]) { //Swap the elements int temp = intArray[j]; intArray[j] = intArray[j+1]; intArray[j+1] = temp; //swap = true; } //comparisons get +1 until the for loop is done sorting comparisons++; } //End for loop } //Return the comparison counter return comparisons; } /************************************************************************************ * * Merge Sort: * This method takes a random array and splits it in half. Once the array is * split in half, it creates a temp0rary array. This temporary array is built by * the method searching the two halves of the original array and puts the information * in order stored in the temporary array. Once all the numbers are in order, the * temporary array is then copied back to the original array. * Precondition: take in an array of random integers * Postcondition: return the random array sorted in ascending order * **********************************************************************************/ public static int mergeSort(int[] intArray) { if(intArray.length >= 2) { int mid = intArray.length / 2; //Create 2 arrays to store half of the data in each int[] first = new int[mid]; //holds first half of array int[] second = new int[intArray.length - mid]; //holds second half of array for(int i = 0; i < first.length; i++) { first[i] = intArray[i]; } for(int i = 0; i < second.length; i++) { second[i] = intArray[mid+i]; } mergeSort(first); mergeSort(second); merge(first, second, intArray); //Merge all together } return comparisons; } //merging first and second halves of mergeSort array public static int merge(int[] first, int[] second, int[] intArray) { int iFirst = 0; int iSecond = 0; int i = 0; //moving the smaller element into intArray while(iFirst < first.length && iSecond < second.length) { comparisons++; if(first[iFirst] < second[iSecond]) { intArray[i] = first[iFirst]; iFirst++; } else { intArray[i] = second[iSecond]; iSecond++; } i++; } //copying the remaining of first array while(iFirst < first.length) { intArray[i] = first[iFirst]; iFirst++; i++; } //copying the remaining of second array while(iSecond < second.length) { intArray[i] = second[iSecond]; iSecond++; i++; } return comparisons; } /************************************************************************************** * Instance methods: * These methods perform actions to the array. * * copyArray()--makes a copy of the array to be used in the main class * so that each method is able to create the same array * * printArray()--prints out the array for display * * randomArray()--creates a random integer array used by all three sorting methods * **************************************************************************************/ public static int[] copyArray(int[] intArray) { //Constructor that creates copyArray int[] copyArray = new int[intArray.length]; //siz equal to the length of the array for(int i = 0; i "); for(int i = 0; i < intArray.length; i++){ System.out.print(intArray[i] + " "); } // end for System.out.println(" "); } // end printArray //Creates a random array that is used for each sorting method public static int[] randomArray(int array, double range){ //Preconditions // Input: size of array(n), range of integers (0 to range) // Assumptions: none //Postconditions // Output: array of random integers 0 to floor(range) // Actions: none int[] intArray = new int[array]; for(int i = 0; i < array; i++){ intArray[i] = (int)(Math.random() * range); } // end for return intArray; } // end randomIntArray } 执行以下行时（或之前）：
- if（intArray [i]> intArray [largestIndex]）{
- if（intArray [j-1]> intArray [j]）{
- if（first [iFirst]
您的mergeSort方法使用递归。 因此，它需要采用比较参数，并将其传递给每个后续方法调用并再次接收结果值。
public static int mergeSort(int[] intArray, int comparisons) { if(intArray.length >= 2) { int mid = intArray.length / 2; //Create 2 arrays to store half of the data in each int[] first = new int[mid]; //holds first half of array int[] second = new int[intArray.length - mid]; //holds second half of array for(int i = 0; i < first.length; i++) { first[i] = intArray[i]; } for(int i = 0; i < second.length; i++) { second[i] = intArray[mid+i]; } comparisons = mergeSort(first, comparisons); comparisons = mergeSort(second, comparisons); comparisons = merge(first, second, intArray, comparisons); //Merge all together } return comparisons; } //merging first and second halves of mergeSort array public static int merge(int[] first, int[] second, int[] intArray, int comparisons) { int iFirst = 0; int iSecond = 0; int i = 0; //moving the smaller element into intArray while(iFirst < first.length && iSecond < second.length) { comparisons++; if(first[iFirst] < second[iSecond]) { intArray[i] = first[iFirst]; iFirst++; } else { intArray[i] = second[iSecond]; iSecond++; } i++; } //copying the remaining of first array while(iFirst < first.length) { intArray[i] = first[iFirst]; iFirst++; i++; } //copying the remaining of second array while(iSecond < second.length) { intArray[i] = second[iSecond]; iSecond++; i++; } return comparisons; }