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72 lines
1.5 KiB

10 months ago
use std::collections::HashSet;
use std::env;
fn er() -> Vec<u64> {
let mut nums = Vec::new();
let size = 4000000;
for n in 0..size+1 { nums.push(true); }
let mut p = 1;
loop {
let mut found = false;
for i in p+1..size {
if nums[i] {
found = true;
p = i;
break;
}
}
if !found { break; }
for i in (2 * p .. size).step_by(p) {
nums[i] = false;
}
}
let mut res = Vec::new();
for i in 2..size {
if nums[i] { res.push(i as u64); }
}
return res;
}
fn span(l: usize, ps: &Vec<u64>, hs: &HashSet<u64>) -> u64 {
let mut sum = 0u64;
let mut max = 0u64;
for i in 0..ps.len() {
sum += ps.get(i).unwrap();
if i >= l {
sum -= ps.get(i - l).unwrap();
}
if sum > 1000000 {
continue;
}
if hs.contains(&sum) && i >= l {
if sum > max {
max = sum;
}
}
}
return max;
}
fn main() {
//env::set_var("RUST_BACKTRACE", "full");
let ps = er();
let mut hs = HashSet::new();
for p in ps.iter() {
hs.insert(*p);
}
let mut max = 0;
//let mut l_max = 0;
for s in 1..ps.len() - 1 {
let m = span(s, &ps, &hs);
if m > 0 {
//l_max = s;
max = m;
println!("{} {}", s, m);
}
}
println!("{}", max);
}