_1128.java

packagecom.fishercoder.solutions.secondthousand;

importjava.util.HashMap;
importjava.util.Map;

publicclass_1128 {
publicstaticclassSolution1 {
publicintnumEquivDominoPairs(int[][] dominoes) {
intm = dominoes.length;
Map<Integer, Integer> map = newHashMap<>();
intcount = 0;
for (inti = 0; i < m; i++) {
intsmaller = Math.min(dominoes[i][0], dominoes[i][1]);
intbigger = Math.max(dominoes[i][0], dominoes[i][1]);
intkey = smaller * 10 + bigger;
count += map.getOrDefault(key, 0);
map.put(key, map.getOrDefault(key, 0) + 1);
 }
returncount;
 }
 }
}