g1701_1800.s1705_maximum_number_of_eaten_apples.Solution Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of leetcode-in-java21 Show documentation

Java-based LeetCode algorithm problem solutions, regularly updated

There is a newer version: 1.38

package g1701_1800.s1705_maximum_number_of_eaten_apples;

// #Medium #Array #Greedy #Heap_Priority_Queue
// #2022_04_24_Time_53_ms_(77.63%)_Space_45.2_MB_(80.26%)

import java.util.PriorityQueue;

/**
 * 1705 - Maximum Number of Eaten Apples\.
 *
 * Medium
 *
 * There is a special kind of apple tree that grows apples every day for `n` days. On the i^th day, the tree grows `apples[i]` apples that will rot after `days[i]` days, that is on day `i + days[i]` the apples will be rotten and cannot be eaten. On some days, the apple tree does not grow any apples, which are denoted by `apples[i] == 0` and `days[i] == 0`.
 *
 * You decided to eat **at most** one apple a day (to keep the doctors away). Note that you can keep eating after the first `n` days.
 *
 * Given two integer arrays `days` and `apples` of length `n`, return _the maximum number of apples you can eat._
 *
 * **Example 1:**
 *
 * **Input:** apples = [1,2,3,5,2], days = [3,2,1,4,2]
 *
 * **Output:** 7
 *
 * **Explanation:** You can eat 7 apples:
 *
 * - On the first day, you eat an apple that grew on the first day. 
 *
 * - On the second day, you eat an apple that grew on the second day. 
 *
 * - On the third day, you eat an apple that grew on the second day. After this day, the apples that grew on the third day rot.
 *
 * - On the fourth to the seventh days, you eat apples that grew on the fourth day.
 *
 * **Example 2:**
 *
 * **Input:** apples = [3,0,0,0,0,2], days = [3,0,0,0,0,2]
 *
 * **Output:** 5
 *
 * **Explanation:** You can eat 5 apples: 
 *
 * - On the first to the third day you eat apples that grew on the first day. 
 *
 * - Do nothing on the fouth and fifth days. 
 *
 * - On the sixth and seventh days you eat apples that grew on the sixth day.
 *
 * **Constraints:**
 *
 * *   `n == apples.length == days.length`
 * *   1 <= n <= 2 * 10⁴
 * *   0 <= apples[i], days[i] <= 2 * 10⁴
 * *   `days[i] = 0` if and only if `apples[i] = 0`.
**/
public class Solution {
    public int eatenApples(int[] apples, int[] days) {
        PriorityQueue minHeap = new PriorityQueue<>((a, b) -> a[0] - b[0]);
        int eatenApples = 0;
        for (int i = 0; i < apples.length || !minHeap.isEmpty(); i++) {
            if (i < apples.length) {
                minHeap.offer(new int[] {i + days[i], apples[i]});
            }
            while (!minHeap.isEmpty() && (minHeap.peek()[0] <= i || minHeap.peek()[1] <= 0)) {
                minHeap.poll();
            }
            if (!minHeap.isEmpty()) {
                eatenApples++;
                minHeap.peek()[1]--;
            }
        }
        return eatenApples;
    }
}