leetcode495. Teemo Attacking

题目要求

In LOL world, there is a hero called Teemo and his attacking can make his enemy Ashe be in poisoned condition. Now, given the Teemo's attacking ascending time series towards Ashe and the poisoning time duration per Teemo's attacking, you need to output the total time that Ashe is in poisoned condition.

You may assume that Teemo attacks at the very beginning of a specific time point, and makes Ashe be in poisoned condition immediately.

Example 1:

Input: [1,4], 2
Output:
Explanation: At time point 1, Teemo starts attacking Ashe and makes Ashe be poisoned immediately.
This poisoned status will last 2 seconds until the end of time point 2.
And at time point 4, Teemo attacks Ashe again, and causes Ashe to be in poisoned status for another 2 seconds.
So you finally need to output 4.

Example 2:

Input: [1,2], 2
Output: 3
Explanation: At time point 1, Teemo starts attacking Ashe and makes Ashe be poisoned.
This poisoned status will last 2 seconds until the end of time point 2.
However, at the beginning of time point 2, Teemo attacks Ashe again who is already in poisoned status.
Since the poisoned status won't add up together, though the second poisoning attack will still work at time point 2, it will stop at the end of time point 3.
So you finally need to output 3.

Note:

1. You may assume the length of given time series array won't exceed 10000.
2. You may assume the numbers in the Teemo's attacking time series and his poisoning time duration per attacking are non-negative integers, which won't exceed 10,000,000.

LOL里面有一个英雄名叫Teemo，它的一个技能是在敌人区域释放毒药并且能够持续一段时间。现在传入一个数组，分别表示Teemo释放技能的时间点，以及一个整数表示技能持续的时间，问敌人一共被毒多长时间？要注意，如果在释放技能期间重复释放技能，技能时间是从当前时间开始重新计算的。

思路和代码

简单来说，该技能释放的时间点一共有两种情况：

1. 无毒
2. 有毒

如果无毒的话，只需要将技能持续时间累加到总时间上即可。而如果有毒的话，就需要计算额外延长的毒药时间，通过 当前时间+技能持续时间-上一个技能持续时间 得出。代码如下：

public int findPoisonedDuration(int[] timeSeries, int duration) {  
    if (timeSeries == null || timeSeries.length == 0) {  
        return 0;  
    }  
    int totalDuration = 0;  
    int timeLimit = 0;  
    for (int time : timeSeries) {  
        if (timeLimit <= time) {  
            totalDuration += duration;  
        } else {  
            totalDuration += time + duration - timeLimit;  
        }  
        timeLimit = time + duration;  
    }  
    return totalDuration;  
}