總價 50元,以4種硬幣(50元, 10元, 5元, 1元)組合1, 0, 0, 00, 5, 0, 00, 4, 2, 00, 4, 1, 50, 4, 0, 100, 3, 4, 00, 3, 3, 50, 3, 2, 100, 3, 1, 150, 3, 0, 200, 2, 6, 00, 2, 5, 50, 2, 4, 100, 2, 3, 150, 2, 2, 200, 2, 1, 250, 2, 0, 300, 1, 8, 00, 1, 7, 50, 1, 6, 100, 1, 5, 150, 1, 4, 200, 1, 3, 250, 1, 2, 300, 1, 1, 350, 1, 0, 400, 0, 10, 00, 0, 9, 50, 0, 8, 100, 0, 7, 150, 0, 6, 200, 0, 5, 250, 0, 4, 300, 0, 3, 350, 0, 2, 400, 0, 1, 450, 0, 0, 50共有 37 種
long n = 3_160_000;double ans = 1;for (; n != 0; n--)ans += (n * 5 + 1) * (n * 5 + 1);print("ans=" + ans); // ans=2.6295430808154338E20