1LL在C++中是什么意思？

Question

看到一段代码，有一句是ans += yes[i] * 1LL * (yes[i] - 1) / 2;,请问1LL是什么意思？在C++中如何使用？
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Answer 1

LL stands for long long, a 64-bit long integer type, newly defined in the C++11 standard. Its usage is an integer type with a larger range. How else do you want to use it?