摘要：Consider equations having the following form: a*x1^2+b*x2^2+c*x3^2+d*x4^2=0 a, b, c, d are integers from the interval [-50,50] and any of them cannot 阅读全文

摘要：Hassan is in trouble. His mathematics teacher has given him a very difficult problem called 5-sum. Please help him. The 5-sum problem is defined as fo 阅读全文

摘要：In the year 8888, the Earth is ruled by the PPF Empire . As the population growing , PPF needs to find more land for the newborns . Finally , PPF deci 阅读全文

摘要：Many people like to solve hard puzzles some of which may lead them to madness. One such puzzle could be finding a hidden prime number in a given text. 阅读全文