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package class_2022_03_2_week;
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// 来自微软
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// 给定一个正数数组arr，长度为N，依次代表N个任务的难度，给定一个正数k
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// 你只能从0任务开始，依次处理到N-1号任务结束，就是一定要从左往右处理任务
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// 只不过，难度差距绝对值不超过k的任务，可以在一天之内都完成
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// 返回完成所有任务的最少天数
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public class Code06_JobMinDays {
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public static int minDays1(int[] arr, int k) {
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int n = arr.length;
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int[] dp = new int[n];
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dp[0] = 1;
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for (int i = 1; i < n; i++) {
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dp[i] = dp[i - 1] + 1;
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int min = arr[i];
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int max = arr[i];
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for (int j = i - 1; j >= 0; j--) {
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min = Math.min(min, arr[j]);
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max = Math.max(max, arr[j]);
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if (max - min <= k) {
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dp[i] = Math.min(dp[i], 1 + (j - 1 >= 0 ? dp[j - 1] : 0));
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} else {
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break;
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}
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}
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}
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return dp[n - 1];
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}
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public static int minDays2(int[] arr, int k) {
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int n = arr.length;
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int[] dp = new int[n];
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int[] windowMax = new int[n];
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int[] windowMin = new int[n];
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int maxL = 0;
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int maxR = 0;
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int minL = 0;
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int minR = 0;
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int L = 0;
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for (int i = 0; i < n; i++) {
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while (maxL < maxR && arr[windowMax[maxR - 1]] <= arr[i]) {
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maxR--;
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}
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windowMax[maxR++] = i;
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while (minL < minR && arr[windowMin[minR - 1]] >= arr[i]) {
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minR--;
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}
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windowMin[minR++] = i;
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while (arr[windowMax[maxL]] - arr[windowMin[minL]] > k) {
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if (windowMax[maxL] == L) {
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maxL++;
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}
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if (windowMin[minL] == L) {
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minL++;
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}
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L++;
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}
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dp[i] = 1 + (L - 1 >= 0 ? dp[L - 1] : 0);
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}
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return dp[n - 1];
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}
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// 为了测试
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public static int[] randomArray(int n, int v) {
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int[] arr = new int[n];
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for (int i = 0; i < n; i++) {
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arr[i] = (int) (Math.random() * v);
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}
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return arr;
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}
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// 为了测试
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public static void main(String[] args) {
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int len = 50;
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int value = 20;
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int testTime = 20000;
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System.out.println("测试开始");
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for (int i = 0; i < testTime; i++) {
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int n = (int) (Math.random() * len) + 1;
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int[] arr = randomArray(n, value);
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int k = (int) (Math.random() * value);
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int ans1 = minDays1(arr, k);
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int ans2 = minDays2(arr, k);
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if (ans1 != ans2) {
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System.out.println("出错了!");
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for (int num : arr) {
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System.out.print(num + " ");
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}
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System.out.println();
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System.out.println("k = " + k);
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System.out.println(ans1);
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System.out.println(ans2);
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break;
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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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