数列的第一项为n，以后各项为前一项的平方根，求数列的前m项的和
da1 <- read.table("D:/R/plyr/1.txt",
header = FALSE)
names(da1) <- c("n","m")
da1 <- as.matrix(da1)
f <- function(x)
{
n <- x[1]
m <- x[2]
a <- numeric(m)
a[1] <- n
for(i in 2:m)
{
a[i] <- sqrt(a[i-1])
}
return(round(sum(a),digits = 2))
}
write.table(
apply(da1,1,f),"D:/R/plyr/1output.txt",
quote = FALSE,
col.names = FALSE,
row.names = FALSE)为了纪念牛客网的第一次作业
