package class20;

import java.util.Arrays;

import java.util.Comparator;

import java.util.PriorityQueue;

// 题目

// 数组arr代表每一个咖啡机冲一杯咖啡的时间，每个咖啡机只能串行的制造咖啡。

// 现在有n个人需要喝咖啡，只能用咖啡机来制造咖啡。

// 认为每个人喝咖啡的时间非常短，冲好的时间即是喝完的时间。

// 每个人喝完之后咖啡杯可以选择洗或者自然挥发干净，只有一台洗咖啡杯的机器，只能串行的洗咖啡杯。

// 洗杯子的机器洗完一个杯子时间为a，任何一个杯子自然挥发干净的时间为b。

// 四个参数：arr, n, a, b

// 假设时间点从0开始，返回所有人喝完咖啡并洗完咖啡杯的全部过程结束后，至少来到什么时间点。

public class Code03_Coffee {

// 验证的方法

// 彻底的暴力

// 很慢但是绝对正确

public static int right(int[] arr, int n, int a, int b) {

int[] times = new int[arr.length];

int[] drink = new int[n];

return forceMake(arr, times, 0, drink, n, a, b);

}

// 每个人暴力尝试用每一个咖啡机给自己做咖啡

public static int forceMake(int[] arr, int[] times, int kth, int[] drink, int n, int a, int b) {

if (kth == n) {

int[] drinkSorted = Arrays.copyOf(drink, kth);

Arrays.sort(drinkSorted);

return forceWash(drinkSorted, a, b, 0, 0, 0);

}

int time = Integer.MAX_VALUE;

for (int i = 0; i < arr.length; i++) {

int work = arr[i];

int pre = times[i];

drink[kth] = pre + work;

times[i] = pre + work;

time = Math.min(time, forceMake(arr, times, kth + 1, drink, n, a, b));

drink[kth] = 0;

times[i] = pre;

}

return time;

}

public static int forceWash(int[] drinks, int a, int b, int index, int washLine, int time) {

if (index == drinks.length) {

return time;

}

// 选择一：当前index号咖啡杯，选择用洗咖啡机刷干净

int wash = Math.max(drinks[index], washLine) + a;

int ans1 = forceWash(drinks, a, b, index + 1, wash, Math.max(wash, time));

// 选择二：当前index号咖啡杯，选择自然挥发

int dry = drinks[index] + b;

int ans2 = forceWash(drinks, a, b, index + 1, washLine, Math.max(dry, time));

return Math.min(ans1, ans2);

}

// 以下为贪心+优良暴力

public static class Machine {

public int timePoint;

public int workTime;

public Machine(int t, int w) {

timePoint = t;

workTime = w;

}

}

public static class MachineComparator implements Comparator<Machine> {

@Override

public int compare(Machine o1, Machine o2) {

return (o1.timePoint + o1.workTime) - (o2.timePoint + o2.workTime);

}

}

// 优良一点的暴力尝试的方法

public static int minTime1(int[] arr, int n, int a, int b) {

PriorityQueue<Machine> heap = new PriorityQueue<Machine>(new MachineComparator());

for (int i = 0; i < arr.length; i++) {

heap.add(new Machine(0, arr[i]));

}

int[] drinks = new int[n];

for (int i = 0; i < n; i++) {

Machine cur = heap.poll();

cur.timePoint += cur.workTime;

drinks[i] = cur.timePoint;

heap.add(cur);

}

return bestTime(drinks, a, b, 0, 0);

}

// drinks 所有杯子可以开始洗的时间

// wash 单杯洗干净的时间（串行）

// air 挥发干净的时间(并行)

// free 洗的机器什么时候可用

// drinks[index.....]都变干净，最早的结束时间（返回）

public static int bestTime(int[] drinks, int wash, int air, int index, int free) {

if (index == drinks.length) {

return 0;

}

// index号杯子 决定洗

int selfClean1 = Math.max(drinks[index], free) + wash;

int restClean1 = bestTime(drinks, wash, air, index + 1, selfClean1);

int p1 = Math.max(selfClean1, restClean1);

// index号杯子 决定挥发

int selfClean2 = drinks[index] + air;

int restClean2 = bestTime(drinks, wash, air, index + 1, free);

int p2 = Math.max(selfClean2, restClean2);

return Math.min(p1, p2);

}

// 贪心+优良尝试改成动态规划

public static int minTime2(int[] arr, int n, int a, int b) {

PriorityQueue<Machine> heap = new PriorityQueue<Machine>(new MachineComparator());

for (int i = 0; i < arr.length; i++) {

heap.add(new Machine(0, arr[i]));

}

int[] drinks = new int[n];

for (int i = 0; i < n; i++) {

Machine cur = heap.poll();

cur.timePoint += cur.workTime;

drinks[i] = cur.timePoint;

heap.add(cur);

}

return bestTimeDp(drinks, a, b);

}

public static int bestTimeDp(int[] drinks, int wash, int air) {

int N = drinks.length;

int maxFree = 0;

for (int i = 0; i < drinks.length; i++) {

maxFree = Math.max(maxFree, drinks[i]) + wash;

}

int[][] dp = new int[N + 1][maxFree + 1];

for (int index = N - 1; index >= 0; index--) {

for (int free = 0; free <= maxFree; free++) {

int selfClean1 = Math.max(drinks[index], free) + wash;

if (selfClean1 > maxFree) {

break; // 因为后面的也都不用填了

}

// index号杯子 决定洗

int restClean1 = dp[index + 1][selfClean1];

int p1 = Math.max(selfClean1, restClean1);

// index号杯子 决定挥发

int selfClean2 = drinks[index] + air;

int restClean2 = dp[index + 1][free];

int p2 = Math.max(selfClean2, restClean2);

dp[index][free] = Math.min(p1, p2);

}

}

return dp[0][0];

}

// for test

public static int[] randomArray(int len, int max) {

int[] arr = new int[len];

for (int i = 0; i < len; i++) {

arr[i] = (int) (Math.random() * max) + 1;

}

return arr;

}

// for test

public static void printArray(int[] arr) {

System.out.print("arr : ");

for (int j = 0; j < arr.length; j++) {

System.out.print(arr[j] + ", ");

}

System.out.println();

}

public static void main(String[] args) {

int len = 10;

int max = 10;

int testTime = 10;

System.out.println("测试开始");

for (int i = 0; i < testTime; i++) {

int[] arr = randomArray(len, max);

int n = (int) (Math.random() * 7) + 1;

int a = (int) (Math.random() * 7) + 1;

int b = (int) (Math.random() * 10) + 1;

int ans1 = right(arr, n, a, b);

int ans2 = minTime1(arr, n, a, b);

int ans3 = minTime2(arr, n, a, b);

if (ans1 != ans2 || ans2 != ans3) {

printArray(arr);

System.out.println("n : " + n);

System.out.println("a : " + a);

System.out.println("b : " + b);

System.out.println(ans1 + " , " + ans2 + " , " + ans3);

System.out.println("===============");

break;

}

}

System.out.println("测试结束");

}

}