[LeetCode] 495 Teemo Attacking

Description

Our hero Teemo is attacking an enemy Ashe with poison attacks! When Teemo attacks Ashe, Ashe gets poisoned for a exactly duration seconds. More formally, an attack at second t will mean Ashe is poisoned during the inclusive time interval [t, t + duration - 1]. If Teemo attacks again before the poison effect ends, the timer for it is reset, and the poison effect will end duration seconds after the new attack.

You are given a non-decreasing integer array timeSeries, where timeSeries[i] denotes that Teemo attacks Ashe at second timeSeries[i], and an integer duration.

Return the total number of seconds that Ashe is poisoned.

Example 1:

Input: timeSeries = [1,4], duration = 2
Output: 4
Explanation: Teemo's attacks on Ashe go as follows:

• At second 1, Teemo attacks, and Ashe is poisoned for seconds 1 and 2.
• At second 4, Teemo attacks, and Ashe is poisoned for seconds 4 and 5.
  Ashe is poisoned for seconds 1, 2, 4, and 5, which is 4 seconds in total.

Example 2:

Input: timeSeries = [1,2], duration = 2
Output: 3
Explanation: Teemo's attacks on Ashe go as follows:

• At second 1, Teemo attacks, and Ashe is poisoned for seconds 1 and 2.
• At second 2 however, Teemo attacks again and resets the poison timer. Ashe is poisoned for seconds 2 and 3.
  Ashe is poisoned for seconds 1, 2, and 3, which is 3 seconds in total.

Constraints:

• 1 <= timeSeries.length <= 10^4
• 0 <= timeSeries[i], duration <= 10^7
• timeSeries is sorted in non-decreasing order.

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풀이

타임시리즈 배열의 요소를 하나씩 본다.

현재 시간에 지속시간을 더한 것이 다음 시간보다 크다면 겹치는 경우이므로, total에 다음 시간에서 현재시간을 뺀 겹치는 시간을 더해준다.

만약 작다면(겹치지 않는다면), total에 지속시간만 더해준다.

마지막에는 total에 지속시간을 더해주고 반환한다.

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코드

class Solution {
    public int findPoisonedDuration(int[] timeSeries, int duration) {
        int total = 0;
        
        for (int i = 0; i < timeSeries.length - 1; i++) {
            int curTime = timeSeries[i];
            int nextTime = timeSeries[i+1];
            
            if (curTime + duration > nextTime) {
                total += nextTime - curTime;
            } else {
                total += duration;
            }
        }
        
        return total + duration;
    }
}

단축시킨 코드

class Solution {
    public int findPoisonedDuration(int[] timeSeries, int duration) {
        int total = 0;
        
        for (int i = 0; i < timeSeries.length - 1; i++) {
            int curTime = timeSeries[i];
            int nextTime = timeSeries[i+1];
            
            total += Math.min(nextTime - curTime, duration);
        }
        
        return total + duration;
    }
}