87 lines
2.5 KiB
Java
87 lines
2.5 KiB
Java
//给你一个数组 points ，其中 points[i] = [xi, yi] 表示 X-Y 平面上的一个点。求最多有多少个点在同一条直线上。
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//
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//
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//
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// 示例 1：
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//
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//
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//输入：points = [[1,1],[2,2],[3,3]]
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//输出：3
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//
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//
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// 示例 2：
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//
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//
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//输入：points = [[1,1],[3,2],[5,3],[4,1],[2,3],[1,4]]
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//输出：4
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//
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//
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//
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//
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// 提示：
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//
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//
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// 1 <= points.length <= 300
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// points[i].length == 2
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// -104 <= xi, yi <= 104
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// points 中的所有点 互不相同
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//
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// Related Topics 几何 哈希表 数学
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// 👍 257 👎 0
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package leetcode.editor.cn;
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import java.util.ArrayList;
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import java.util.HashMap;
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import java.util.List;
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import java.util.Map;
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//149:直线上最多的点数
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public class MaxPointsOnALine {
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public static void main(String[] args) {
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//测试代码
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Solution solution = new MaxPointsOnALine().new Solution();
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}
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//力扣代码
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//leetcode submit region begin(Prohibit modification and deletion)
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class Solution {
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public int maxPoints(int[][] points) {
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Map<Map<Double, Double>, List<Integer>> map = new HashMap<>();
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int count = 1;
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for (int i = 0; i < points.length; i++) {
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for (int j = i + 1; j < points.length; j++) {
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double sub = points[j][0] - points[i][0];
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double x, y;
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if (sub == 0) {
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x = points[i][0];
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y = Integer.MAX_VALUE;
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} else {
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x = (points[j][1] - points[i][1]) / sub;
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y = (points[j][0] * points[i][1] - points[i][0] * points[j][1]) / sub;
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}
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Map<Double, Double> key = new HashMap<>();
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key.put(x, y);
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List<Integer> list = new ArrayList<>();
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if (map.containsKey(key)) {
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list = map.get(key);
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if (!list.contains(i)) {
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list.add(i);
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}
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if (!list.contains(j)) {
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list.add(j);
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}
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} else {
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list.add(i);
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list.add(j);
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}
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count = Math.max(count, list.size());
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map.put(key, list);
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}
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}
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return count;
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}
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}
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//leetcode submit region end(Prohibit modification and deletion)
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} |