数组拆分

Posted 2020-10-02

温习并学习下算法，记录设计地点滴。

数组拆分是将一个无序数组，拆分成两个子数组，子数组A地元素全部比数组元素小，子数组B地元素全部比数组元素大。

 

代码如下：

package test;

import java.util.Arrays;

public class PartitionPolicy {

    public void part(int[] array, int key) {
        
        // swap
        int temp = array[key];
        array[key] = array[array.length-1];
        array[array.length-1] = temp;
                
        int j=-1;
        for (int i=0; i<array.length; i++) {
            
            if (array[i] < array[key]) {
                
                j++;
                temp = array[i];
                array[i] = array[j];
                array[j] = temp;
            }
        }
        temp = array[j+1];
        array[j+1] = array[array.length-1];
        array[array.length-1] = temp;
    }
    
    public static void main(String[] args) {
        
        PartitionPolicy p = new PartitionPolicy();
        int[] toSortArr = {4,2,9,77,6,33,100,1,2,56,20};
        p.part(toSortArr, 5);
        System.out.println(Arrays.toString(toSortArr));
    }
}

 

运行结果如下：

[4, 2, 9, 6, 1, 2, 33, 77, 20, 56, 100]