摘要： 寻找比n小的所有质数的方法。2是质数， 2*i都是质数，同样3是质数，3*i也都是质数代码如下1 int n;2 vector prime (n+1, true);3 prime[0] = prime[1] = false;4 for (int i=2; i<=n; ++i)5 if (prime[i])6 if (i * 1ll * i <= n)7 for (int j=i*i; j<=n; j+=i)8 prime[j] = false; 阅读全文

摘要： 1. notation:n = number of featuresx(i) = input (features) of ithtraining example= value of feature j inithtraining example2. Hypothesis:3. Cost function:4. Gradient descent:Repeat { }substituting cost function, thenRepeat { (simultaneously updateθj for j = 0, ... n)}5. Mean normalizationreplace ... 阅读全文