原题链接:Leetcode 495. Teemo Attacking
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 <= 104
- 0 <= timeSeries[i], duration <= 107
- timeSeries is sorted in non-decreasing order.
方法一:遍历
思路:
timeSeries数组已经保证了是非递减排序
C++代码:
class Solution {
public:
int findPoisonedDuration(vector<int>& timeSeries, int duration) {
int ans = 0, last = -1; // last为上一次攻击的结束点
for(int i = 0; i < timeSeries.size(); i++ ){
int cur = timeSeries[i] + duration - 1; // 本次攻击持续时间
if(last < timeSeries[i])
ans += duration;
else
ans += cur - last;
last = cur;
}
return ans;
}
};