我需要随机洗牌以下数组:
int[] solutionArray = {1, 2, 3, 4, 5, 6, 6, 5, 4, 3, 2, 1};
有什么函数可以做到吗?
我需要随机洗牌以下数组:
int[] solutionArray = {1, 2, 3, 4, 5, 6, 6, 5, 4, 3, 2, 1};
有什么函数可以做到吗?
当前回答
还有另一种方法,还没有发布
//that way, send many object types diferentes
public anotherWayToReciveParameter(Object... objects)
{
//ready with array
final int length =objects.length;
System.out.println(length);
//for ready same list
Arrays.asList(objects);
}
这种方法更简单,取决于上下文
其他回答
看看Collections类,特别是shuffle(…)。
使用随机类
public static void randomizeArray(int[] arr) {
Random rGenerator = new Random(); // Create an instance of the random class
for (int i =0; i< arr.length;i++ ) {
//Swap the positions...
int rPosition = rGenerator.nextInt(arr.length); // Generates an integer within the range (Any number from 0 - arr.length)
int temp = arr[i]; // variable temp saves the value of the current array index;
arr[i] = arr[rPosition]; // array at the current position (i) get the value of the random generated
arr[rPosition] = temp; // the array at the position of random generated gets the value of temp
}
for(int i = 0; i<arr.length; i++) {
System.out.print(arr[i]); //Prints out the array
}
}
最简单的解决方案,这种随机洗牌数组。
String location[] = {"delhi","banglore","mathura","lucknow","chandigarh","mumbai"};
int index;
String temp;
Random random = new Random();
for(int i=1;i<location.length;i++)
{
index = random.nextInt(i+1);
temp = location[index];
location[index] = location[i];
location[i] = temp;
System.out.println("Location Based On Random Values :"+location[i]);
}
这是knuth shuffle算法。
public class Knuth {
// this class should not be instantiated
private Knuth() { }
/**
* Rearranges an array of objects in uniformly random order
* (under the assumption that <tt>Math.random()</tt> generates independent
* and uniformly distributed numbers between 0 and 1).
* @param a the array to be shuffled
*/
public static void shuffle(Object[] a) {
int n = a.length;
for (int i = 0; i < n; i++) {
// choose index uniformly in [i, n-1]
int r = i + (int) (Math.random() * (n - i));
Object swap = a[r];
a[r] = a[i];
a[i] = swap;
}
}
/**
* Reads in a sequence of strings from standard input, shuffles
* them, and prints out the results.
*/
public static void main(String[] args) {
// read in the data
String[] a = StdIn.readAllStrings();
// shuffle the array
Knuth.shuffle(a);
// print results.
for (int i = 0; i < a.length; i++)
StdOut.println(a[i]);
}
}
Random rnd = new Random();
for (int i = ar.length - 1; i > 0; i--)
{
int index = rnd.nextInt(i + 1);
// Simple swap
int a = ar[index];
ar[index] = ar[i];
ar[i] = a;
}
顺便说一下,我注意到这段代码返回了一个ar.length - 1个数的元素,所以如果你的数组有5个元素,新的打乱的数组将有4个元素。这是因为for循环说i>0。如果你改变为i>=0,你得到所有的元素洗牌。