Data commit

Task/Smith-numbers/D/smith-numbers.d

@@ -0,0 +1,53 @@
+import std.stdio;
+
+void main() {
+    int cnt;
+    for (int n=1; n<10_000; n++) {
+        auto factors = primeFactors(n);
+        if (factors.length > 1) {
+            int sum = sumDigits(n);
+            foreach (f; factors) {
+                sum -= sumDigits(f);
+            }
+            if (sum==0) {
+                writef("%4s  ", n);
+                cnt++;
+            }
+            if (cnt==10) {
+                cnt = 0;
+                writeln();
+            }
+        }
+    }
+}
+
+auto primeFactors(int n) {
+    import std.array : appender;
+    auto result = appender!(int[]);
+
+    for (int i=2; n%i==0; n/=i) {
+        result.put(i);
+    }
+
+    for (int i=3; i*i<=n; i+=2) {
+        while (n%i==0) {
+            result.put(i);
+            n/=i;
+        }
+    }
+
+    if (n!=1) {
+        result.put(n);
+    }
+
+    return result.data;
+}
+
+int sumDigits(int n) {
+    int sum;
+    while (n > 0) {
+        sum += (n%10);
+        n /= 10;
+    }
+    return sum;
+}