题解 | #数组中只出现一次的数（其它数出现k次）#

package suanfa.array;

import java.util.HashMap;
import java.util.Map;

public class FoundOnceNumber {

public static void main(String[] args) {

    int[] nums = new int[]{5, 4, 1, 1, 5, 1, 5};

    int result = foundOnceNumber(nums, 3);
}

//遍历数组 arr[i]  作为key 出现的次数最位value。
public static int foundOnceNumber(int[] arr, int k) {

    Map<Integer, Integer> map = new HashMap<>();

    for (int i = 0; i < arr.length; i++) {
        map.put(arr[i], 1 + map.getOrDefault(arr[i], 0));
    }

    for (Map.Entry<Integer, Integer> entry : map.entrySet()) {
        int tims = entry.getValue();
        if (tims == 1) {
            return entry.getKey();
        }
    }
    return -1;
}

}