如何使用rust-0.10进行调试?它适用于较小的数字,如13195 ...... 我想我用uint
达到了一些限制use std::vec;
use std::num;
use std::iter;
fn int_sqrt(n: uint) -> uint {
num::sqrt(n as f64) as uint
}
fn simple_sieve(limit: uint) -> ~[uint] {
if limit < 2 {
return ~[];
}
let mut primes = vec::from_elem(limit + 1, true);
for prime in iter::range_inclusive(2, int_sqrt(limit) + 1) {
if primes[prime] {
for multiple in iter::range_step(prime * prime, limit + 1, prime) {
primes[multiple] = false
}
}
}
iter::range_inclusive(2, limit).filter(|&n| primes[n]).collect()
}
fn main() {
let limit: uint = 600851475143;
let limithalf: uint = limit/2 as uint;
let primes = simple_sieve(limithalf);
let sieved: ~[uint] = primes.move_iter().filter(|&n| limit % n == 0).collect();
println!("{:?}", sieved);
let mut max = 0;
let f = |x: uint| if x > max { max = x };
for x in sieved.iter() {
f(*x);
}
println!("{}", max);
}
答案 0 :(得分:2)
问题在于您尝试执行的大量分配:vec::from_elem
中的simple_sieve
调用尝试分配600851475143/2
个字节,即大约280 GB。分配失败(即malloc
返回NULL),ATM只会导致Rust中止。
这个更简单的程序表明了问题:
extern crate libc;
fn main() {
let n = 600851475143 / 2;
let p = unsafe {libc::malloc(n as libc::size_t)};
println!("alloc {}", p)
}
为我打印alloc 0x0
。尝试使用较小的数字。 :)