結果
| 問題 | No.797 Noelちゃんとピラミッド |
| ユーザー |
 kusomushi
|
| 提出日時 | 2019-07-10 05:32:34 |
| 言語 | Java (openjdk 23) |
| 結果 |
AC
|
| 実行時間 | 339 ms / 2,000 ms |
| コード長 | 6,040 bytes |
| コンパイル時間 | 2,522 ms |
| コンパイル使用メモリ | 81,192 KB |
| 実行使用メモリ | 46,572 KB |
| 最終ジャッジ日時 | 2024-10-13 08:29:47 |
| 合計ジャッジ時間 | 18,606 ms |
|
ジャッジサーバーID （参考情報） |
judge3 / judge5 |
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| ファイルパターン | 結果 |
|---|---|
| sample | AC * 3 |
| other | AC * 60 |
ソースコード
import java.io.*;
import java.util.Arrays;
import java.util.StringJoiner;
import java.util.StringTokenizer;
import java.util.function.Function;
public class Main {
static int N;
static int[] A;
public static void main(String[] args) {
FastScanner sc = new FastScanner(System.in);
N = sc.nextInt();
A = sc.nextIntArray(N);
System.out.println(solve());
}
static int solve() {
FermatCombination fc = new FermatCombination(N+1);
int ans = 0;
for (int i = 0; i < N; i++) {
ans = add(ans, mul(A[i], fc.comb(N-1, i)));
}
return ans;
}
static int MOD = 1_000_000_007;
static int pow(int base, long exp) {
if (exp == 0) return 1;
int ans = 1;
base %= MOD;
while (exp > 0) {
if ((exp & 1) == 1) {
ans = mul(ans, base);
}
base = mul(base, base);
exp = exp >> 1;
}
return ans;
}
static int sub(int a, int b) {
int c = a - b;
if (c < 0) c += MOD;
return c;
}
static int div(int a, int b) {
return mul(a, pow(b, MOD - 2));
}
static int add(int a, int b) {
int c = a + b;
if (c >= MOD) c %= MOD;
return c;
}
static int mul(int a, int b) {
long c = (long) a * b;
if (c >= MOD) c %= MOD;
return (int) c;
}
static class FermatCombination {
private final int size;
private final int[] factorial; // n -> factorial(n)
private final int[] inverse; // n -> inverse(factorial(n))
FermatCombination(int size) {
this.size = size;
factorial = new int[size + 1];
inverse = new int[size + 1];
init();
}
private void init() {
factorial[0] = 1;
factorial[1] = 1;
inverse[0] = 1;
inverse[1] = 1;
for (int i = 2; i <= size; i++) {
factorial[i] = mul(factorial[i - 1], i);
inverse[i] = pow(factorial[i], MOD - 2);
}
}
int comb(int n, int k) {
if (n > size) throw new RuntimeException("wtf : size=" + size + " n=" + n);
return mul(mul(factorial[n], inverse[k]), inverse[n - k]);
}
// 重複組み合わせ
// k種類からn個選ぶ場合の数
int hcomb(int k, int n) {
return comb(k + n - 1, n);
}
int group(int n, int g, int k) {
// C(n, g) * C(n-g, g)... / k!
// n! / (n-gk)! / g! ^ k / k!
int ret = factorial[n]; // n!
ret = mul(ret, inverse[n - g * k]); // 1 / (n-gk)!
ret = mul(ret, pow(inverse[g], k)); // 1 / (g! ^ k)
ret = mul(ret, inverse[k]); // 1 / k!
return ret;
}
}
@SuppressWarnings("unused")
static class FastScanner {
private BufferedReader reader;
private StringTokenizer tokenizer;
FastScanner(InputStream in) {
reader = new BufferedReader(new InputStreamReader(in));
tokenizer = null;
}
String next() {
if (tokenizer == null || !tokenizer.hasMoreTokens()) {
try {
tokenizer = new StringTokenizer(reader.readLine());
} catch (IOException e) {
throw new RuntimeException(e);
}
}
return tokenizer.nextToken();
}
String nextLine() {
if (tokenizer == null || !tokenizer.hasMoreTokens()) {
try {
return reader.readLine();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
return tokenizer.nextToken("\n");
}
long nextLong() {
return Long.parseLong(next());
}
int nextInt() {
return Integer.parseInt(next());
}
int[] nextIntArray(int n) {
int[] a = new int[n];
for (int i = 0; i < n; i++)
a[i] = nextInt();
return a;
}
int[] nextIntArray(int n, int delta) {
int[] a = new int[n];
for (int i = 0; i < n; i++)
a[i] = nextInt() + delta;
return a;
}
long[] nextLongArray(int n) {
long[] a = new long[n];
for (int i = 0; i < n; i++)
a[i] = nextLong();
return a;
}
}
static <A> void writeLines(A[] as, Function<A, String> f) {
PrintWriter pw = new PrintWriter(System.out);
for (A a : as) {
pw.println(f.apply(a));
}
pw.flush();
}
static void writeLines(int[] as) {
PrintWriter pw = new PrintWriter(System.out);
for (int a : as) pw.println(a);
pw.flush();
}
static void writeLines(long[] as) {
PrintWriter pw = new PrintWriter(System.out);
for (long a : as) pw.println(a);
pw.flush();
}
static int max(int... as) {
int max = Integer.MIN_VALUE;
for (int a : as) max = Math.max(a, max);
return max;
}
static int min(int... as) {
int min = Integer.MAX_VALUE;
for (int a : as) min = Math.min(a, min);
return min;
}
static void debug(Object... args) {
StringJoiner j = new StringJoiner(" ");
for (Object arg : args) {
if (arg instanceof int[]) j.add(Arrays.toString((int[]) arg));
else if (arg instanceof long[]) j.add(Arrays.toString((long[]) arg));
else if (arg instanceof double[]) j.add(Arrays.toString((double[]) arg));
else if (arg instanceof Object[]) j.add(Arrays.toString((Object[]) arg));
else j.add(arg.toString());
}
System.err.println(j.toString());
}
}