結果

問題 No.763 Noelちゃんと木遊び
ユーザー T101010101
提出日時 2023-02-06 19:28:01
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 97 ms / 2,000 ms
コード長 3,627 bytes
コンパイル時間 3,802 ms
コンパイル使用メモリ 257,008 KB
最終ジャッジ日時 2025-02-10 11:23:13
ジャッジサーバーID
(参考情報)
judge4 / judge2
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ファイルパターン 結果
other AC * 21
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ソースコード

diff #
プレゼンテーションモードにする

#pragma region Macros
#include <bits/extc++.h>
using namespace std;
using namespace __gnu_pbds;
// using namespace __gnu_cxx;
// #include <boost/multiprecision/cpp_int.hpp>
// namespace mp = boost::multiprecision;
// using Bint = mp::cpp_int;
#define TO_STRING(var) # var
#define pb emplace_back
#define int ll
#define endl '\n'
using ll = long long;
using ld = long double;
const ld PI = acos(-1);
const ld EPS = 1e-10;
const int INF = 1 << 30;
const ll INFL = 1LL << 61;
// const int MOD = 998244353;
const int MOD = 1000000007;
// __attribute__((constructor))
// void constructor() {
// ios::sync_with_stdio(false);
// cin.tie(nullptr);
// // ifstream in("input.txt");
// // cin.rdbuf(in.rdbuf());
// cout << fixed << setprecision(15);
// }
template<int mod> class modint{
public:
int val = 0;
modint(int x = 0) { while (x < 0) x += mod; val = x % mod; }
modint(const modint &r) { val = r.val; }
modint operator -() { return modint(-val); }
modint operator +(const modint &r) { return modint(*this) += r; }
modint operator -(const modint &r) { return modint(*this) -= r; }
modint operator *(const modint &r) { return modint(*this) *= r; }
modint operator /(const modint &r) { return modint(*this) /= r; }
modint &operator +=(const modint &r) {
val += r.val;
if (val >= mod) val -= mod;
return *this;
}
modint &operator -=(const modint &r) {
if (val < r.val) val += mod;
val -= r.val;
return *this;
}
modint &operator *=(const modint &r) {
val = val * r.val % mod;
return *this;
}
modint &operator /=(const modint &r) {
int a = r.val, b = mod, u = 1, v = 0;
while (b) {
int t = a / b;
a -= t * b; swap(a, b);
u -= t * v; swap(u, v);
}
val = val * u % mod;
if (val < 0) val += mod;
return *this;
}
bool operator ==(const modint& r) { return this -> val == r.val; }
bool operator <(const modint& r) { return this -> val < r.val; }
bool operator !=(const modint& r) { return this -> val != r.val; }
};
using mint = modint<MOD>;
istream &operator >>(istream &is, mint& x) {
int t; is >> t;
x = t;
return (is);
}
ostream &operator <<(ostream &os, const mint& x) {
return os << x.val;
}
mint modpow(const mint &a, int N) {
if (N == 0) return 1;
mint t = modpow(a, N / 2);
t = t * t;
if (N & 1) t = t * a;
return t;
}
int modpow(int x, int N, int mod) {
int ret = 1;
while (N > 0) {
if (N % 2 == 1) ret = ret * x % mod;
x = x * x % mod;
N /= 2;
}
return ret;
}
int ceil(int x, int y) { return (x > 0 ? (x + y - 1) / y : x / y); }
#pragma endregion
vector<int> ans;
vector<bool> flag;
void dfs(vector<vector<int>> &G, int v, int p) {
flag[v] = true;
for (auto nv : G[v]) {
if (flag[nv]) continue;
dfs(G, nv, v);
}
// if (G[v].size() == 1) ans[v] = true;
bool f = true;
for (auto nv : G[v]) {
if (nv == p) continue;
if (ans[nv]) f = false;
}
if (f) ans[v] = true;
}
signed main() {
int N;
cin >> N;
vector<vector<int>> G(N);
for (int i = 0; i < N - 1; i++) {
int u, v;
cin >> u >> v;
u--; v--;
G[u].pb(v);
G[v].pb(u);
}
ans.assign(N, 0);
flag.assign(N, false);
dfs(G, 0, -1);
int cnt = 0;
for (int i = 0; i < N; i++) {
if (ans[i]) {
// cout << i + 1 << " ";
cnt++;
}
}
cout << cnt << endl;
}
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