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@@ -0,0 +1,77 @@
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+import java.util.HashMap;
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+
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+/**
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+ * Definition for a point.
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+ * class Point {
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+ * int x;
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+ * int y;
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+ * Point() { x = 0; y = 0; }
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+ * Point(int a, int b) { x = a; y = b; }
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+ * }
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+ */
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+class Solution {
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+ class Pair {
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+ final int _1;
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+ final int _2;
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+
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+ Pair(int _1, int _2) {
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+ this._1 = _1;
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+ this._2 = _2;
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+ }
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+
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+ @Override
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+ public int hashCode() {
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+ int hash = 7;
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+ hash = 71 * hash + _1;
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+ hash = 71 * hash + _2;
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+ return hash;
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+ }
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+
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+ @Override
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+ public boolean equals(Object obj) {
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+ if (this == obj) return true;
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+ if (!(obj instanceof Pair)) return false;
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+ Pair p = (Pair) obj;
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+ return p._1 == _1 && p._2 == _2;
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+ }
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+ }
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+
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+ public int maxPoints(Point[] points) {
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+ int res = 0;
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+ for (int i = 0; i < points.length; i++) {
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+ HashMap<Pair, Integer> map = new HashMap<>();
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+ int cnt = 1;
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+ for (int j = 0; j < points.length; j++) {
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+ if (j == i) continue;
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+ Point p1 = points[i];
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+ Point p2 = points[j];
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+ if (p1.x == p2.x && p1.y == p2.y) {
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+ cnt++;
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+ continue;
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+ }
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+ Pair slope = getSlope(p1, p2);
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+ Integer freq = map.getOrDefault(slope, 0);
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+ map.put(slope, freq + 1);
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+ }
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+ int max = 0;
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+ for (Integer val : map.values()) {
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+ max = Math.max(max, val);
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+ }
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+ res = Math.max(res, max + cnt);
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+ }
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+ return res;
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+ }
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+
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+ private Pair getSlope(Point p1, Point p2) {
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+ int dx = p1.x - p2.x;
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+ int dy = p1.y - p2.y;
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+ if (dx == 0) return new Pair(p1.x, 0);
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+ if (dy == 0) return new Pair(0, p1.y);
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+ int d = gcd(dx, dy);
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+ return new Pair(dx / d, dy / d);
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+ }
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+
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+ private int gcd(int m, int n) {
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+ return n == 0 ? m : gcd(n, m % n);
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+ }
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+}
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