Add Project Euler problem #455 Dlang solution

pe-0455/dub.json

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+{
+	"authors": [
+		"menja"
+	],
+	"copyright": "Copyright © 2024, menja",
+	"description": "A minimal D application.",
+	"license": "proprietary",
+	"name": "pe-0455"
+}

pe-0455/source/app.d

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+// Powers with Trailing Digits
+// https://projecteuler.net/problem=455
+
+import std.stdio;
+import std.datetime.stopwatch;
+
+ulong modularExponentiation(ulong base, ulong exponent, ulong modulus) {
+    ulong result = 1;
+
+    while (exponent > 0) {
+        if (exponent % 2 != 0) {
+            result = (result * base) % modulus;
+        }
+        base = (base * base) % modulus;
+        exponent >>= 1;
+    }
+
+    return result;
+}
+
+void main() {
+    auto timer = StopWatch(AutoStart.yes);
+
+    ulong totalSum = 0;
+
+    for (ulong number = 2; number <= 1000000; number += !(++number % 10)) {
+        ulong current, next;
+
+        for (current = number; ; current = next) {
+            next = modularExponentiation(number, current, 1000000000);
+            if (next == current) break;
+        }
+
+        totalSum += current;
+    }
+
+    writefln("\nProject Euler #455\nAnswer: %s", totalSum);
+    writefln("Elapsed time: %s milliseconds.\n", timer.peek.total!"msecs"());
+}
+