Sandbox::https://github.com/prashanthigupta/leetcode-algorithms/blob/master/src/NumberOfBoomerangs.java

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import java.util.HashMap;

import java.util.Map;

public class NumberOfBoomerangs {

public int numberOfBoomerangs(int[][] points) {

if (points.length == 0) {

return 0;

}

int boomerangs = 0;

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

for (int i = 0; i < points.length; i++) {

for (int j = 0 ; j < points.length; j++) {

if (i == j) {

continue;

}

int distance = getDistance(points[i], points[j]);

distances.put(distance, distances.getOrDefault(distance, 0) + 1);

}

for (int frequency : distances.values()) {

boomerangs += frequency * (frequency - 1);

}

distances.clear();

}

return boomerangs;

}

private int getDistance(int[] point1, int[] point2) {

int x_diff = point1[0] - point2[0];

int y_diff = point1[1] - point2[1];

return x_diff * x_diff + y_diff * y_diff;

}