https://leetcode-cn.com/problems/number-of-good-pairs/
Java
public int numIdenticalPairs(int[] nums) {
if (nums.length < 0) {
return 0;
}
int[] counts = new int[101];
int count = 0;
for (int num : nums) {
count += counts[num];
counts[num]++;
}
return count;
}
原文：https://www.cnblogs.com/baidu-com/p/13762168.html