039 ok

039/main.rs

@@ -0,0 +1,39 @@
+use std::collections::HashMap;
+const SIZE: u32 = 1000u32;
+
+fn squares() -> HashMap<u32, u32> {
+    let mut res = HashMap::new();
+    for n in 1..=SIZE {
+        res.insert(n*n, n);
+    }
+    res
+}
+fn main() {
+    let mut sq = squares();
+    let mut ps = HashMap::new();
+    for a in 1..SIZE {
+        for b in 1..SIZE {
+            let c2 = a*a + b*b;
+            if sq.contains_key(&c2) {
+                let c = *sq.get(&c2).unwrap();
+                let p = a + b + c;
+                if p > SIZE { continue; }
+                if !ps.contains_key(&p) {
+                    ps.insert(p, 1);
+                } else {
+                    let count = ps.get(&p).unwrap();
+                    ps.insert(p, count + 1);
+                }
+            }
+        }
+    }
+    let mut max_v = 0u32;
+    let mut max_k = 0u32;
+    for (k, v) in ps.iter() {
+        if *v > max_v {
+            max_v = *v;
+            max_k = *k;
+        }
+    }
+    println!("{}", max_k);
+}