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package class26;
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import java.util.Arrays;
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import java.util.Comparator;
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import java.util.List;
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import java.util.TreeSet;
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public class Code01_MinRange {
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// 本题为求最小包含区间
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// 测试链接 :
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// https://leetcode.com/problems/smallest-range-covering-elements-from-k-lists/
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public static class Node {
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public int val;
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public int arr;
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public int idx;
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public Node(int value, int arrIndex, int index) {
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val = value;
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arr = arrIndex;
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idx = index;
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}
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}
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public static class NodeComparator implements Comparator<Node> {
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@Override
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public int compare(Node a, Node b) {
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return a.val != b.val ? (a.val - b.val) : (a.arr - b.arr);
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}
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}
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public static int[] smallestRange(List<List<Integer>> nums) {
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int N = nums.size();
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TreeSet<Node> set = new TreeSet<>(new NodeComparator());
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for (int i = 0; i < N; i++) {
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set.add(new Node(nums.get(i).get(0), i, 0));
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}
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int r = Integer.MAX_VALUE;
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int a = 0;
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int b = 0;
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while (set.size() == N) {
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Node max = set.last();
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Node min = set.pollFirst();
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if (max.val - min.val < r) {
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r = max.val - min.val;
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a = min.val;
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b = max.val;
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}
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if (min.idx < nums.get(min.arr).size() - 1) {
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set.add(new Node(nums.get(min.arr).get(min.idx + 1), min.arr, min.idx + 1));
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}
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}
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return new int[] { a, b };
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}
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// 以下为课堂题目，在main函数里有对数器
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public static int minRange1(int[][] m) {
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int min = Integer.MAX_VALUE;
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for (int i = 0; i < m[0].length; i++) {
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for (int j = 0; j < m[1].length; j++) {
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for (int k = 0; k < m[2].length; k++) {
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min = Math.min(min,
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Math.abs(m[0][i] - m[1][j]) + Math.abs(m[1][j] - m[2][k]) + Math.abs(m[2][k] - m[0][i]));
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}
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}
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}
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return min;
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}
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public static int minRange2(int[][] matrix) {
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int N = matrix.length;
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TreeSet<Node> set = new TreeSet<>(new NodeComparator());
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for (int i = 0; i < N; i++) {
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set.add(new Node(matrix[i][0], i, 0));
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}
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int min = Integer.MAX_VALUE;
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while (set.size() == N) {
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min = Math.min(min, set.last().val - set.first().val);
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Node cur = set.pollFirst();
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if (cur.idx < matrix[cur.arr].length - 1) {
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set.add(new Node(matrix[cur.arr][cur.idx + 1], cur.arr, cur.idx + 1));
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}
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}
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return min << 1;
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}
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public static int[][] generateRandomMatrix(int n, int v) {
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int[][] m = new int[3][];
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int s = 0;
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for (int i = 0; i < 3; i++) {
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s = (int) (Math.random() * n) + 1;
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m[i] = new int[s];
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for (int j = 0; j < s; j++) {
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m[i][j] = (int) (Math.random() * v);
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}
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Arrays.sort(m[i]);
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}
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return m;
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}
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public static void main(String[] args) {
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int n = 20;
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int v = 200;
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int t = 1000000;
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System.out.println("测试开始");
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for (int i = 0; i < t; i++) {
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int[][] m = generateRandomMatrix(n, v);
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int ans1 = minRange1(m);
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int ans2 = minRange2(m);
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if (ans1 != ans2) {
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System.out.println("出错了!");
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}
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}
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System.out.println("测试结束");
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}
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}
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