printf <- function(...) cat(sprintf(...))
 
f <- function(p, n, r)
{
    if (p < 1 | p > n | r <= 0) return()
    r <- min(n, r)
    a <- r %/% 2
    b <- (r - 1) %/% 2
    min(n - a, max(1 + b, p)) + -b:a
}
 
Q <- list(
    c(1, 10, 5), c(3, 10, 5), c(5, 10, 5), c(8, 10, 5), c(10, 10, 5),
    c(5, 10, 0), c(5, 10, 4), c(0, 10, 5), c(11, 10, 5), c(1, 3, 5)
)
 
for (q in Q) {
    printf("p = %d, n = %d, r = %d\n", q[1], q[2], q[3])
    printf("[%s]\n", toString(f(q[1], q[2], q[3])))
    printf("\n")
}

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