Calculate Number Frequency

男娘i 2022-08-23 11:50 126阅读 0赞

腾讯面试题：  
给你 10 分钟时间，根据上排给出十个数，在其下排填出对应的十个数，  
要求下排每个数都是先前上排那十个数在下排出现的次数。  
上排的十个数如下：

【0，1，2，3，4，5，6，7，8，9】

举一个例子，  
数值: 0,1,2,3,4,5,6,7,8,9  
分配: 6,2,1,0,0,0,1,0,0,0  
0 在下排出现了 6 次，1 在下排出现了 2 次，  
2 在下排出现了 1 次，3 在下排出现了 0 次....

以此类推..

package shuai.study.frequency;
    
    /**
     * @author shengshu
     * 
     */
    public class NumberFrequency {
    	private final int len = 10;
    
    	private int[] numberArray = null;
    	private int[] frequencyArray = null;
    
    	public NumberFrequency() {
    		numberArray = new int[len];
    		frequencyArray = new int[len];
    	}
    
    	// Initialize numberArray
    	public void initNumberArray() {
    		for (int i = 0; i < len; i++) {
    			numberArray[i] = i;
    		}
    	}
    
    	// Get final frequencyArray
    	public int[] getFrequencyArray() {
    		while (isSetFrequencyArray(numberArray)) {
    			isSetFrequencyArray(numberArray);
    		}
    
    		return frequencyArray;
    	}
    
    	// Whether set frequencyArray according to judging 'frequencyArray[i] != frequency'
    	public boolean isSetFrequencyArray(int[] numberArray) {
    		boolean setNextFrequencyFlag = false;
    
    		for (int i = 0; i < len; i++) {
    			int frequency = getFrequency(numberArray[i]);
    
    			if (frequencyArray[i] != frequency) {
    				frequencyArray[i] = frequency;
    				setNextFrequencyFlag = true;
    			}
    		}
    
    		return setNextFrequencyFlag;
    	}
    
    	// Get numberArray's element(number) frequency 
    	public int getFrequency(int number) {
    		int frequency = 0;
    
    		for (int i = 0; i < len; i++) {
    			if (frequencyArray[i] == number) {
    				frequency++;
    			}
    		}
    
    		return frequency;
    	}
    
    	// Print array
    	public void printArray(int[] array) {
    		for (int i = 0; i < array.length; i++) {
    			System.out.print(array[i] + "\t");
    		}
    	}
    
    	// Main thread
    	public static void main(String[] args) {
    		NumberFrequency numberFrequency = new NumberFrequency();
    
    		numberFrequency.initNumberArray();
    		int[] frequencyArray = numberFrequency.getFrequencyArray();
    		numberFrequency.printArray(frequencyArray);
    	}
    }