基本排序算法

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1. 插入排序法

        /** * 插入排序法 * @param a */static void insertionSort( ArrayList<Integer> a){int j;for( int p = 1; p < a.size(); p++ ){Integer tmp = a.get(p);for( j = p; j > 0 && tmp.compareTo(a.get(j - 1)) < 0; j-- ) {System.out.println("change " + a.get(j) + "  " + a.get(j - 1));a.set(j, a.get(j - 1));}a.set(j, tmp);System.out.println(" p = " + p + " change " + a.get(j) + "  " + tmp);}}

2.希尔排序法

       /** * 希尔排序 * @param a */static void shellSort( ArrayList<Integer> a ){int j;for( int gap = a.size() / 2; gap > 0; gap /= 2 ){for( int i = gap; i < a.size(); i++ ){Integer tmp = a.get(i);for( j = i; j >= gap && tmp.compareTo(a.get(j - gap)) < 0; j-=gap ){System.out.println("change " + a.get(j) + "  " + a.get(j - gap));a.set(j, a.get(j - gap));}System.out.println(" i = " + i + " change " + a.get(j) + "  " + tmp);a.set(j, tmp);}System.out.println(" gap  = " + gap);}}

3. 归并排序

       /** * 归并排序 * @param a * @param tmpArray * @param left * @param right */static void mergeSort( ArrayList<Integer> a, ArrayList<Integer> tmpArray, int left, int right ){if( left < right ){int center = ( left + right ) / 2;mergeSort(a, tmpArray, left, center);mergeSort(a, tmpArray, center + 1, right);merge(a, tmpArray, left, center + 1, right);}}static void merge( ArrayList<Integer> a, ArrayList<Integer> tmpArray, int leftPos, int rightPos, int rightEnd ){int leftEnd = rightPos - 1;int tmpPos = leftPos;int numElements = rightEnd - leftPos + 1;while( leftPos <= leftEnd && rightPos <= rightEnd ){if( a.get(leftPos).compareTo(a.get(rightPos)) <= 0 ){tmpArray.set(tmpPos++, a.get(leftPos++));}else{tmpArray.set(tmpPos++, a.get(rightPos++));}}while( leftPos <= leftEnd ){tmpArray.set(tmpPos++, a.get(leftPos++));}while( rightPos <= rightEnd ){tmpArray.set(tmpPos++, a.get(rightPos++));}for( int i = 0; i < numElements; i++, rightEnd--){a.set(rightEnd, tmpArray.get(rightEnd));}}

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