495 - Teemo Attacking.

Easy

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:

• <code>1 <= timeSeries.length <= 10⁴</code>

• <code>0 <= timeSeriesi, duration <= 10⁷</code>

• timeSeries is sorted in non-decreasing order.