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相比较ATan，ATan2究竟有什么不同？本篇介绍一下ATan2的用法及使用条件。对于tan(θ) =y/x:θ=ATan(y/x)求出的θ取值范围是[-PI/2, PI/2]。θ=ATan2(y, x)求出的θ取值范围是[-PI, PI]。当 (x,y) 在第一象限, 0 <θ<PI/2.当(x,... 阅读全文
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#include#include#include#includeconst double pi=3.141592653;int main(){ int t; scanf("%d",&t); while(t--){ int n; scanf("%d",&n); double a... 阅读全文
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Encrypting passwords is one of the most important problems nowadays, and you trust only the encryp- tion algorithms which you invented, and you have j 阅读全文
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Problem Description For a tree, which nodes and edges are all weighted, the ratio of it is calculated according to the following equation. Given a com 阅读全文