give code for this in the format shown in image

Criado em: 12 de julho de 2025

Respondido usando O3 por Chat01

Pergunta

87819068_SKC1272025_1818.png87819068_SKC1272025_1818.png
87819068_SKC1272025_18145.png87819068_SKC1272025_18145.png
87819068_SKC1272025_1828.png87819068_SKC1272025_1828.png

give code for this in the format shown in image

Pensamento

Designing solution approach

The user asks for Java code following a specific format given in images. The question involves processing N distinct points on a cartesian plane to find how many straight lines can pass through at least three points.

I need to design an algorithm where, for all pairs of points, I calculate the line parameters and identify how many lines meet this condition. Let me structure this carefully to fit the required format, making sure the methods and class layout match the expectations.

Designing line-detection algorithm

For this task, I need to count distinct lines that pass through at least three points. To do this, I’ll compute the line’s slope using fractions and possibly the normalized line equation. I can use the slope and intercept or the normalized integer coefficients A, B, and C (with gcd normalization) to identify unique lines. By mapping points to line representations, I can check if lines pass through three or more points. I’ll write this up in Java as specified, including imports, classes, and the main method with proper formatting.

Providing the solution

I’ll write the Java code to solve the problem of determining how many straight lines pass through at least three points. The

Thought for 27 seconds

Resposta

Here’s a drop-in replacement for the skeleton you see in the screenshot (Java 8).
Just copy-paste it over the template and run the tests.

java
import java.util.*; public class TestClass { /*----------------------------------------------------------- Returns the number of DISTINCT straight lines that pass through at least three of the N given points. ------------------------------------------------------------*/ public static int maxLines(int N, int[] x, int[] y) { /* We encode each line in reduced-integer form (A,B,C) for ax + by + c = 0, with gcd(|A|,|B|,|C|) = 1 and a canonical sign, so every pair that defines the same geometric line maps to the same key. */ class LineKey { final int A, B, C; LineKey(int A, int B, int C) { this.A = A; this.B = B; this.C = C; } @Override public boolean equals(Object o) { if (this == o) return true; if (!(o instanceof LineKey)) return false; LineKey k = (LineKey) o; return A == k.A && B == k.B && C == k.C; } @Override public int hashCode() { return Objects.hash(A, B, C); } } Map<LineKey, Set<Integer>> ptsOnLine = new HashMap<>(); for (int i = 0; i < N; ++i) { for (int j = i + 1; j < N; ++j) { int A = y[j] - y[i]; // Δy int B = x[i] - x[j]; // –Δx (so Ax + By is constant) int C = x[j] * y[i] - x[i] * y[j]; /* reduce (A,B,C) to lowest terms */ int g = gcd(gcd(Math.abs(A), Math.abs(B)), Math.abs(C)); if (g != 0) { A /= g; B /= g; C /= g; } /* canonical sign: first non-zero coefficient positive */ if (A < 0 || (A == 0 && B < 0) || (A == 0 && B == 0 && C < 0)) { A = -A; B = -B; C = -C; } LineKey key = new LineKey(A, B, C); ptsOnLine.computeIfAbsent(key, k -> new HashSet<>()).add(i); ptsOnLine.get(key).add(j); } } int answer = 0; for (Set<Integer> s : ptsOnLine.values()) { if (s.size() >= 3) answer++; } return answer; } /* simple iterative gcd */ private static int gcd(int a, int b) { while (b != 0) { int t = a % b; a = b; b = t; } return a; } /*-----------------------------------------------------------*/ public static void main(String[] args) { Scanner sc = new Scanner(System.in); int N = sc.nextInt(); int[] x = new int[N]; int[] y = new int[N]; for (int i = 0; i < N; ++i) { x[i] = sc.nextInt(); y[i] = sc.nextInt(); } System.out.print(maxLines(N, x, y)); } }

How it works (quick recap)

  • Enumerate every pair of points ( ≈ N²/2, fine for N ≤ 100).
  • Convert the pair to a unique, reduced (A,B,C) signature for the line.
  • Record which points lie on each signature in a Set.
  • Count the signatures whose set holds ≥ 3 distinct indices.

Compartilhar esta Q&A