在R中编写组合

# 计算组合数C(n, k)
combination <- function(n, k) {
  return(factorial(n) / (factorial(k) * factorial(n - k)))
}

# 示例
n <- 5
k <- 2
cat("C(", n, ",", k, ") =", combination(n, k))

# 生成从n个元素中取出k个元素的所有组合
combinations <- function(elements, k) {
  return(combn(elements, k))
}

# 示例
elements <- c("A", "B", "C", "D")
k <- 2
cat("Combinations of", k, "elements from", paste(elements, collapse = ", "), ":\n")
print(combinations(elements, k))

# 使用gmp包处理大数阶乘
library(gmp)
combination_large <- function(n, k) {
  return(as.bigq(factorial(n)) / (factorial(k) * factorial(n - k)))
}

# 示例
n <- 100
k <- 50
cat("C(", n, ",", k, ") =", combination_large(n, k))