delete pics to save space

7.1737.cpp

@@ -0,0 +1,86 @@
+#include<cstdio>
+#include<cstring>
+#include<iostream>
+#include<algorithm>
+#define ll long long
+using namespace std;
+const int N = 60, S = 600;
+int n;
+struct A{
+	int a[S], len;
+	inline A operator / (const int x) const {
+		A ans;
+		memset(ans.a, 0, sizeof(ans.a));
+		ans.len = 0;
+		int num = 0;
+		for (int i = len; i; i--) {
+			num = num * 10 + a[i];
+			ans.a[i] = num / x;
+			num %= x;
+			if (!ans.len && ans.a[i]) ans.len = i;
+		}
+		return ans;
+	}
+	inline A operator + (const A x) const {
+		A ans;
+		memset(ans.a, 0, sizeof(ans.a));
+		for (int i = 1; i <= max(len, x.len); i++) {
+			ans.a[i] += a[i] + x.a[i];
+			ans.a[i+1] = ans.a[i] / 10;
+			ans.a[i] %= 10;
+		}
+		ans.len = max(len, x.len);
+		if (ans.a[ans.len+1]) ++ans.len;
+		return ans;
+	}
+	inline A operator * (const A x) const {
+		A ans;
+		memset(ans.a, 0, sizeof(ans.a));
+		for (int i = 1; i <= len; i++)
+			for (int j = 1; j <= x.len; j++) {
+				ans.a[i+j-1] += a[i] * x.a[j];
+				ans.a[i+j] += ans.a[i+j-1] / 10;
+				ans.a[i+j-1] %= 10;
+			}
+		ans.len = len + x.len - 1;
+		if (ans.a[ans.len+1]) ++ans.len;
+		return ans;
+	}
+} f[N], p[N];
+
+inline A C(int x, int y) {
+	A ans;
+	ans.len = ans.a[1] = 1;
+	for (int i = y, j = 1; j <= x; i--, j++) {
+		int t = i;
+		A tmp;
+		tmp.len = 0;
+		while (t) {
+			tmp.a[++tmp.len] = t % 10;
+			t /= 10;
+		}
+		ans = ans * tmp / j;
+	}
+	return ans;
+}
+
+inline void print(A x) {
+	for (int i = x.len; i; i--) printf("%d", x.a[i]);
+	puts("");
+}
+
+int main() {
+	for (int i = 1; i <= 50; i++) {
+		ll t = (1ll << i) - 1;
+		while (t) {
+			p[i].a[++p[i].len] = t % 10;
+			t /= 10;
+		}
+	}
+	f[1].len = f[2].len = f[1].a[1] = f[2].a[1] = 1;
+	for (int i = 3; i <= 50; i++)
+		for (int j = 1; j <= i - 1; j++)
+			f[i] = f[i] + C(j - 1, i - 2) * f[j] * f[i-j] * p[j];
+	while (cin >> n && n) print(f[n]);
+	return 0;
+}