Add Solution.java

solution/1400-1499/1453.Maximum Number of Darts Inside of a Circular Dartboard/Solution.java

@@ -0,0 +1,53 @@
+import java.util.*;
+
+public class Solution {
+    public int numPoints(int[][] darts, int r) {
+        int n = darts.length;
+        int maxDarts = 1;
+
+        for (int i = 0; i < n; i++) {
+            for (int j = i + 1; j < n; j++) {
+                List<double[]> centers = possibleCenters(darts[i][0], darts[i][1], darts[j][0], darts[j][1], r);
+                for (double[] center : centers) {
+                    maxDarts = Math.max(maxDarts, countDarts(center[0], center[1], darts, r));
+                }
+            }
+        }
+        return maxDarts;
+    }
+
+    private List<double[]> possibleCenters(int x1, int y1, int x2, int y2, int r) {
+        List<double[]> centers = new ArrayList<>();
+        double dx = x2 - x1;
+        double dy = y2 - y1;
+        double d = Math.sqrt(dx * dx + dy * dy);
+        if (d > 2 * r) {
+            return centers;
+        }
+        double midX = (x1 + x2) / 2.0;
+        double midY = (y1 + y2) / 2.0;
+        double distToCenter = Math.sqrt(r * r - (d / 2.0) * (d / 2.0));
+        double offsetX = distToCenter * dy / d;
+        double offsetY = distToCenter * -dx / d;
+
+        centers.add(new double[]{midX + offsetX, midY + offsetY});
+        centers.add(new double[]{midX - offsetX, midY - offsetY});
+        return centers;
+    }
+
+    private int countDarts(double x, double y, int[][] darts, int r) {
+        int count = 0;
+        for (int[] dart : darts) {
+            if (Math.sqrt(Math.pow(dart[0] - x, 2) + Math.pow(dart[1] - y, 2)) <= r + 1e-7) {
+                count++;
+            }
+        }
+        return count;
+    }
+
+    public static void main(String[] args) {
+        Solution solution = new Solution();
+        System.out.println(solution.numPoints(new int[][]{{-2,0},{2,0},{0,2},{0,-2}}, 2)); // Output: 4
+        System.out.println(solution.numPoints(new int[][]{{-3,0},{3,0},{2,6},{5,4},{0,9},{7,8}}, 5)); // Output: 5
+    }
+}