init

problems/p30/Cargo.toml

@@ -0,0 +1,6 @@
+[package]
+name = "p30"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]

problems/p30/src/main.rs

@@ -0,0 +1,26 @@
+// >>> 9**5*6
+// 354294
+// >>> 9**5*7
+// 413343
+//
+// 推测n < 999999
+
+fn is_fifth_power_sum(num: u32) -> bool {
+    let mut digits: Vec<u32> = Vec::new();
+    let mut a = num / 10;
+    let mut b = num % 10;
+    while a != 0 {
+        digits.push(b);
+        b = a % 10;
+        a /= 10;
+    }
+    digits.push(b);
+
+    let sum: u32 = digits.iter().map(|x| x.pow(5)).sum();
+    sum == num
+}
+
+fn main() {
+    let sum_of_is_sum: u32 = (2..999999).filter(|n| is_fifth_power_sum(*n)).sum();
+    println!("{sum_of_is_sum}");
+}