#3315. C++-循环for-计算S=1+2-3+4-5+6-...+(或-)n结果并打印（1<=n<=1000000000000）
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ID: 3315
Type: Default
1000ms
256MiB
Tried: 26
Accepted: 10
Difficulty: 6
Uploaded By:
编创小匠 (paifuture)
C++-循环for-计算S=1+2-3+4-5+6-...+(或-)n结果并打印（1<=n<=1000000000000）
Background
Description
计算S=1+2-3+4-5+6-...+(或-)n结果并打印（1<=n<=1000000000000）
n为输入值
Format
Input
Output
Samples
1000000000000
500000000002
99999999999
-49999999998
5
-1
Limitation
1s, 1024KiB for each test case.