044 ok

044/main.rs

@@ -0,0 +1,31 @@
+use std::collections::HashSet;
+
+fn main() {
+    let mut hs = HashSet::new();
+    for n in 1..10000 {
+        let pn = n * ( 3*n -1 ) / 2;
+        hs.insert(pn);
+    }
+    let mut D = 10000000;
+    for p in hs.iter() {
+        for q in hs.iter() {
+            if q <= p {
+                continue;
+            }
+        
+            let s = *p + *q;
+            if !hs.contains(&s) {
+                continue;
+            }
+            let d = *q - *p;
+            if !hs.contains(&d) {
+                continue;
+            }
+            if d < D {
+                D = d;
+            }
+        }
+    }
+    println!("{}", D);
+
+}