050

050/main.rs

@@ -0,0 +1,71 @@
+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);
+
+}