結果

問題 No.1520 Zigzag Sum
コンテスト
ユーザー goodbaton
提出日時 2021-05-28 23:23:44
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
WA  
実行時間 -
コード長 3,974 bytes
コンパイル時間 1,215 ms
コンパイル使用メモリ 119,580 KB
最終ジャッジ日時 2025-01-21 20:20:49
ジャッジサーバーID
（参考情報） 		judge2 / judge5
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ファイルパターン 結果
sample WA * 1
other AC * 4 WA * 3
権限があれば一括ダウンロードができます
コンパイルメッセージ
main.cpp: In function ‘void solve()’:
main.cpp:168:8: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
  168 |   scanf("%d%d", &H, &W);
      |   ~~~~~^~~~~~~~~~~~~~~~
main.cpp: In function ‘int main()’:
main.cpp:184:8: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
  184 |   scanf("%d", &T);
      |   ~~~~~^~~~~~~~~~

ソースコード

diff # 

#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>

#include <algorithm>
#include <bitset>
#include <complex>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>

#include <cassert>
#include <functional>

using ll = long long;
using namespace std;

template<typename A, typename B>
bool chmin(A &a, const B b) {
  if (a <= b) return false;
  a = b;
  return true;
}

template<typename A, typename B>
bool chmax(A &a, const B b) {
  if (a >= b) return false;
  a = b;
  return true;
}

#ifndef LOCAL
#define debug(...) ;
#else
#define debug(...) cerr << __LINE__ << " : " << #__VA_ARGS__ << " = " << _tostr(__VA_ARGS__) << endl;

template<typename T>
ostream &operator<<(ostream &out, const vector<T> &v);

template<typename T1, typename T2>
ostream &operator<<(ostream &out, const pair<T1, T2> &p) {
  out << "{" << p.first << ", " << p.second << "}";
  return out;
}

template<typename T>
ostream &operator<<(ostream &out, const vector<T> &v) {
  out << '{';
  for (const T &item : v) out << item << ", ";
  out << "\b\b}";
  return out;
}

void _tostr_rec(ostringstream &oss) {
  oss << "\b\b \b";
}

template<typename Head, typename... Tail>
void _tostr_rec(ostringstream &oss, Head &&head, Tail &&...tail) {
  oss << head << ", ";
  _tostr_rec(oss, forward<Tail>(tail)...);
}

template<typename... T>
string _tostr(T &&...args) {
  ostringstream oss;
  int size = sizeof...(args);
  if (size > 1) oss << "{";
  _tostr_rec(oss, forward<T>(args)...);
  if (size > 1) oss << "}";
  return oss.str();
}
#endif

constexpr int mod = 1'000'000'007; //1e9+7(prime number)
constexpr int INF = 1'000'000'000; //1e9
constexpr ll LLINF = 2'000'000'000'000'000'000LL; //2e18
constexpr int SIZE = 200010;

vector<ll> factmemo, factmemoInv;
ll factmemoMod = -1;

ll factorial(int n, int M) {
  if (factmemoMod == M) return factmemo[n];
  if (n <= 1) return 1;

  ll res = 1;
  for (int i = 1; i <= n; i++) res = res * i % M;
  return res;
}

ll power(ll k, ll n, int M) {
  ll res = 1;
  for (; n; n /= 2) {
    if (n & 1) res = res * k % M;
    k = k * k % M;
  }
  return res;
}

void initFactorial(int n, int M) {
  assert(factmemoMod == -1 || factmemoMod == M);
  int prevSize = factmemo.size();
  factmemoMod = M;
  factmemo.resize(max(prevSize, n + 1), 0);
  factmemoInv.resize(max(prevSize, n + 1), 0);
  factmemo[0] = 1;
  for (int i = max(1, prevSize); i <= n; i++) factmemo[i] = factmemo[i - 1] * i % M;
  if (prevSize <= n) factmemoInv[n] = power(factmemo[n], M - 2, M);
  for (int i = n; i > prevSize; i--) factmemoInv[i - 1] = factmemoInv[i] * i % M;
}

//nCm nPm nHm (mod M)

/*Combination*/
ll C(int n, int m, int M) {
  if (n < m) return 0;
  if (m == 0 || n == m) return 1;

  if (factmemoMod == M || factmemoMod == -1)
    initFactorial(max(n, m), M);

  if (factmemoMod == M)
    return factmemo[n] * factmemoInv[m] % M * factmemoInv[n - m] % M;

  ll numer = factorial(n, M);
  ll denom = factorial(m, M) * factorial(n - m, M) % M;

  denom = power((int)denom, M - 2, M);

  return numer * denom % M;
}
/*Permutation*/
ll P(int n, int m, int M) {
  if (n < m) return 0;
  if (m == 0) return 1;

  if (factmemoMod == M || factmemoMod == -1)
    initFactorial(max(n, m), M);

  if (factmemoMod == M)
    return factmemo[n] * factmemoInv[n - m] % M;

  ll numer = factorial(n, M);
  ll denom = factorial(n - m, M);

  denom = power((int)denom, M - 2, M);

  return numer * denom % M;
}
/*Combination with Repetitions*/
ll H(int n, int m, int M) {
  if (n == 0 && m == 0) return 1;
  return C(n + m - 1, m, M);
}

void solve() {
  int H, W;

  scanf("%d%d", &H, &W);
  H--;
  W--;

  ll ans = C(H + W - 2, H - 1, mod) * (ll)(H + W - 1) * 2;

  if (H == 1 || W == 1) {
    ans = 0;
  }

  printf("%lld\n", ans % mod);
}

int main() {
  int T;

  scanf("%d", &T);

  while (T--) {
    solve();
  }

  return 0;
}
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