結果
問題 | No.2235 Line Up Colored Balls |
ユーザー |
|
提出日時 | 2023-07-26 21:26:26 |
言語 | C#(csc) (csc 3.9.0) |
結果 |
AC
|
実行時間 | 71 ms / 2,000 ms |
コード長 | 3,273 bytes |
コンパイル時間 | 1,085 ms |
コンパイル使用メモリ | 114,588 KB |
実行使用メモリ | 26,496 KB |
最終ジャッジ日時 | 2024-10-03 07:51:51 |
合計ジャッジ時間 | 6,514 ms |
ジャッジサーバーID (参考情報) |
judge4 / judge1 |
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ファイルパターン | 結果 |
---|---|
sample | AC * 4 |
other | AC * 55 |
コンパイルメッセージ
Microsoft (R) Visual C# Compiler version 3.9.0-6.21124.20 (db94f4cc) Copyright (C) Microsoft Corporation. All rights reserved.
ソースコード
using System;using static System.Console;using System.Linq;using System.Collections.Generic;class Program{static int NN => int.Parse(ReadLine());static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();public static void Main(){Solve();}static void Solve(){var n = NN;var a = NList;var sum = a.Sum();var mod = 1_000_000_007;var revsum = Exp(sum, mod - 2, mod);var ans = (long)sum;foreach (var ai in a){ans = (ans + mod - (long)ai * (ai - 1) % mod * revsum % mod) % mod;}WriteLine(ans);}static long Exp(int n, int k, int mod){if (k == 0) return 1;if (k == 1) return n % mod;var half = Exp(n, k / 2, mod);var result = (half * half) % mod;return ((k % 2) == 0) ? result : ((result * n) % mod);}static List<int[]> NCRList(int n, int r){var res = new List<int[]>();_NCRList(n, r, new List<int>(), res);return res;}static void _NCRList(int n, int r, List<int> list, List<int[]> res){if (list.Count == r) res.Add(list.ToArray());for (var i = list.Count == 0 ? 0 : (list.Last() + 1); i < n; ++i){list.Add(i);_NCRList(n, r, list, res);list.RemoveAt(list.Count - 1);}}class NCR{int[] facts;int[] revFacts;int mod;public NCR(int n, int mod){facts = new int[n + 1];revFacts = new int[n + 1];this.mod = mod;facts[0] = 1;var tmp = 1L;for (var i = 1; i <= n; ++i){tmp = (tmp * i) % mod;facts[i] = (int)tmp;}tmp = Exp(facts[n], mod - 2);revFacts[n] = (int)tmp;for (var i = n; i > 1; --i){tmp = (tmp * i) % mod;revFacts[i - 1] = (int)tmp;}revFacts[0] = 1;}public long Exp(long n, long k){n = n % mod;if (k == 0) return 1;if (k == 1) return n;var half = Exp(n, k / 2);var result = (half * half) % mod;return ((k % 2) == 0) ? result : ((result * n) % mod);}public long Calc(int n, int r){return (long)facts[n] * revFacts[r] % mod * revFacts[n - r] % mod;}/// <summary>nが大きくrが小さい場合の計算</summary>public long Calc2(int n, int r){var tmp = 1L;for (var i = 0; i < r; ++i){tmp = tmp * (n - i) % mod;}return tmp * revFacts[r] % mod;}public long NPR(int n, int r){return (long)facts[n] * revFacts[r] % mod;}public long Fact(int n){return facts[n];}public long RevFact(int n){return revFacts[n];}}}