Dry Spells

Difficulty: 1000 3000 ms 128 MB

implementation

Daily rainfall amounts are given. A dry spell is a maximal run of ≥ 3 consecutive zero-rain days. Count the dry spells.

Input: the first line has N; the second line has the N rainfall values.

Output: the number of dry spells.

Constraints:

• 1 ≤ N ≤ 10⁵
• 0 ≤ rain ≤ 30

Sample Tests

8
5 0 0 0 2 0 0 1

1

3
0 0 0

1

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