Question

Any know how can I get the mode value from an array? For example, if I have a array with difference number, how can I use Java to search out which number is appears the most?

Answer 1

Completes in O(n) as opposed to O(n^2). Requires arrays of length > 0.

public static int getMode(int[] values) {   HashMap<Integer,Integer> freqs = new HashMap<Integer,Integer>();    for (int val : values) {     Integer freq = freqs.get(val);     freqs.put(val, (freq == null ? 1 : freq+1));   }    int mode = 0;   int maxFreq = 0;    for (Map.Entry<Integer,Integer> entry : freqs.entrySet()) {     int freq = entry.getValue();     if (freq > maxFreq) {       maxFreq = freq;       mode = entry.getKey();     }   }    return mode; }