题目描述
In a flower bed, there are N flowers, numbered 1,2,......,N. Initially, the heights of all flowers are 0.
You are given a sequence h={h_1,h_2,h_3,......} as input. You would like to change the height of Flower k to h_k for all $k (1 \leq k \leq N)$, by repeating the following "watering" operation:
- Specify integers l and r. Increase the height of Flower x by 1 for all x such that $l \leq x \leq r$.
Find the minimum number of watering operations required to satisfy the condition.
-----Constraints-----
- $1 \leq N \leq 100$
- $0 \leq h_i \leq 100$
- All values in input are integers.
-----Input-----
Input is given from Standard Input in the following format:
N
h_1 h_2 h_3 ...... h_N
-----Output-----
Print the minimum number of watering operations required to satisfy the condition.
-----Sample Input-----
4
1 2 2 1
-----Sample Output-----
2
The minimum number of watering operations required is 2.
One way to achieve it is:
- Perform the operation with (l,r)=(1,3).
- Perform the operation with (l,r)=(2,4).
输入格式
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输出格式
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