数组小工具2

整形的数组小工具
  1 package algorithms.self.tools;
  2 
  3 import java.util.Arrays;
  4 
  5 /**
  6  * This is a class to implement Integer array tools
  7  * 
  8  * @author ygh 2017年3月14日
  9  */
 10 public class IntegerArrayTools {
 11 
 12     /**
 13      * Print a int[] into console
 14      * 
 15      * @param arr The array need to print
 16      */
 17     public static void toStringIntArray(int[] arr) {
 18         System.out.println(Arrays.toString(arr));
 19     }
 20 
 21     /**
 22      * Print a int[][] into console
 23      * 
 24      * @param arr The array need to print
 25      */
 26     public static void toTwoDimensionalString(int[][] arr) {
 27         int row = arr.length;
 28         for (int i = 0; i < row; i++) {
 29             toStringIntArray(arr[i]);
 30         }
 31     }
 32 
 33     /**
 34      * Get a random array by size and max value
 35      * 
 36      * @param size The size the new array you want to create
 37      * @param maxValue The max value in the array;
 38      * @return A random array
 39      */
 40     public static int[] getRandomArray(int size, int maxValue) {
 41         int[] arr = new int[size];
 42         for (int i = 0; i < size; i++) {
 43             arr[i] = getIntRandomValue(maxValue);
 44         }
 45         return arr;
 46     }
 47 
 48     /**
 49      * Get a random that less than max value
 50      * 
 51      * @param maxValue The max value you get the random number
 52      * @return A random number less than max value
 53      */
 54     public static int getIntRandomValue(int maxValue) {
 55         return (int) (Math.random() * maxValue);
 56     }
 57 
 58     /**
 59      * Get a random value in a integer array
 60      * 
 61      * @param arr A value come from this array
 62      * @return A random value comes from this array
 63      */
 64     public static int getRandomValue(int[] arr) {
 65         int length = arr.length;
 66         return (arr[getIntRandomValue(length)]);
 67     }
 68 
 69     /**
 70      * Get the max value in a Array.
 71      * 
 72      * @param arr[] The max value come from
 73      * @return The max value in this array
 74      */
 75     public static int getMaxValue(int arr[]) {
 76         int max = arr[0];
 77         for (int i = 1; i < arr.length - 1; i++) {
 78             if (max < arr[i]) {
 79                 max = arr[i];
 80             }
 81         }
 82         return max;
 83     }
 84 
 85     /**
 86      * Get a two-dimensional integer array
 87      * 
 88      * @param row The size of row
 89      * @param column The size of column
 90      * @param maxValue The max value in this array
 91      * @return a new two-dimensional integer array
 92      */
 93     public static int[][] getRandomTwoDimensionalArray(int row, int column, int maxValue) {
 94         int[][] arr = new int[row][column];
 95         for (int i = 0; i < row; i++) {
 96             arr[i] = getRandomArray(column, maxValue);
 97         }
 98 
 99         return arr;
100     }
101 
102     /**
103      * Get average of an integer array
104      * 
105      * @param arr The array provide data
106      * @return The average of this array
107      */
108     public static double getArrayAverage(int[] arr) {
109         int length = arr.length;
110         int sum = 0;
111         for (int i = 0; i < length; i++) {
112             sum += arr[i];
113         }
114         return (sum / length);
115     }
116 
117     /**
118      * Copy an array to new array
119      * 
120      * @param arr The array needed to copy
121      * @return The copied array
122      */
123     public static int[] copy(int arr[]) {
124         int length = arr.length;
125         int newArr[] = new int[length];
126         for (int i = 0; i < length; i++) {
127             newArr[i] = arr[i];
128         }
129         return newArr;
130     }
131 
132     /**
133      * Reverse the elements within an array
134      * 
135      * @param arr An array want to reverse all elements
136      */
137     public static void reverse(int[] arr) {
138         int tmp;
139         int length = arr.length;
140         for (int i = 0; i < length / 2; i++) {
141             tmp = arr[i];
142             arr[i] = arr[length - 1 - i];
143             arr[length - 1 - i] = tmp;
144         }
145     }
146 
147     /**
148      * Transpose a two-dimensional square array
149      * 
150      * @param arr
151      */
152     public static void transposition(int[][] arr) {
153         int row = arr.length;
154         int temp;
155         for (int i = 0; i < row; i++) {
156             for (int j = 0; j < i; j++) {
157                 temp = arr[i][j];
158                 arr[i][j] = arr[j][i];
159                 arr[j][i] = temp;
160             }
161         }
162     }
163 
164     /**
165      * Get a integer array sum
166      * @param arr The array to provide the data
167      * @return The sum of all elements in the array
168      */
169     public static int getIntegrArraySum(int arr[]) {
170         int sum = 0;
171         for (int i = 0; i < arr.length; i++) {
172             sum = sum + arr[i];
173         }
174         return sum;
175     }
176 
177 }