g2401_2500.s2453_destroy_sequential_targets.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 g2401_2500.s2453_destroy_sequential_targets;

// #Medium #Array #Hash_Table #Counting #2022_12_15_Time_33_ms_(96.27%)_Space_58.9_MB_(95.38%)

import java.util.HashMap;

/**
 * 2453 - Destroy Sequential Targets\.
 *
 * Medium
 *
 * You are given a **0-indexed** array `nums` consisting of positive integers, representing targets on a number line. You are also given an integer `space`.
 *
 * You have a machine which can destroy targets. **Seeding** the machine with some `nums[i]` allows it to destroy all targets with values that can be represented as `nums[i] + c * space`, where `c` is any non-negative integer. You want to destroy the **maximum** number of targets in `nums`.
 *
 * Return _the **minimum value** of_ `nums[i]` _you can seed the machine with to destroy the maximum number of targets._
 *
 * **Example 1:**
 *
 * **Input:** nums = [3,7,8,1,1,5], space = 2
 *
 * **Output:** 1
 *
 * **Explanation:** If we seed the machine with nums[3], then we destroy all targets equal to 1,3,5,7,9,... In this case, we would destroy 5 total targets (all except for nums[2]). It is impossible to destroy more than 5 targets, so we return nums[3].
 *
 * **Example 2:**
 *
 * **Input:** nums = [1,3,5,2,4,6], space = 2
 *
 * **Output:** 1
 *
 * **Explanation:** Seeding the machine with nums[0], or nums[3] destroys 3 targets. It is not possible to destroy more than 3 targets. Since nums[0] is the minimal integer that can destroy 3 targets, we return 1.
 *
 * **Example 3:**
 *
 * **Input:** nums = [6,2,5], space = 100
 *
 * **Output:** 2
 *
 * **Explanation:** Whatever initial seed we select, we can only destroy 1 target. The minimal seed is nums[1].
 *
 * **Constraints:**
 *
 * *   1 <= nums.length <= 10⁵
 * *   1 <= nums[i] <= 10⁹
 * *   1 <= space <= 10⁹
**/
public class Solution {
    public int destroyTargets(int[] nums, int space) {
        HashMap map = new HashMap<>();
        for (int num : nums) {
            int reminder = num % space;
            int freq = map.getOrDefault(reminder, 0);
            map.put(reminder, freq + 1);
        }
        int maxCount = 0;
        int ans = Integer.MAX_VALUE;
        for (int count : map.values()) {
            maxCount = Math.max(count, maxCount);
        }
        for (int val : nums) {
            if (map.get(val % space) == maxCount) {
                ans = Math.min(ans, val);
            }
        }
        return ans;
    }
}