結果

問題 No.2638 Initial fare
ユーザー Forested
提出日時 2024-02-19 21:23:02
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 62 ms / 2,000 ms
コード長 6,452 bytes
コンパイル時間 2,052 ms
コンパイル使用メモリ 201,876 KB
最終ジャッジ日時 2025-02-19 16:32:24
ジャッジサーバーID
(参考情報)
judge3 / judge2
このコードへのチャレンジ
(要ログイン)
ファイルパターン 結果
sample AC * 3
other AC * 25
権限があれば一括ダウンロードができます

ソースコード

diff #
プレゼンテーションモードにする

#ifndef LOCAL
#define FAST_IO
#endif
// ============
#include <bits/stdc++.h>
#define OVERRIDE(a, b, c, d, ...) d
#define REP2(i, n) for (i32 i = 0; i < (i32)(n); ++i)
#define REP3(i, m, n) for (i32 i = (i32)(m); i < (i32)(n); ++i)
#define REP(...) OVERRIDE(__VA_ARGS__, REP3, REP2)(__VA_ARGS__)
#define PER2(i, n) for (i32 i = (i32)(n)-1; i >= 0; --i)
#define PER3(i, m, n) for (i32 i = (i32)(n)-1; i >= (i32)(m); --i)
#define PER(...) OVERRIDE(__VA_ARGS__, PER3, PER2)(__VA_ARGS__)
#define ALL(x) begin(x), end(x)
#define LEN(x) (i32)(x.size())
using namespace std;
using u32 = unsigned int;
using u64 = unsigned long long;
using i32 = signed int;
using i64 = signed long long;
using f64 = double;
using f80 = long double;
using pi = pair<i32, i32>;
using pl = pair<i64, i64>;
template <typename T>
using V = vector<T>;
template <typename T>
using VV = V<V<T>>;
template <typename T>
using VVV = V<V<V<T>>>;
template <typename T>
using VVVV = V<V<V<V<T>>>>;
template <typename T>
using PQR = priority_queue<T, V<T>, greater<T>>;
template <typename T>
bool chmin(T &x, const T &y) {
if (x > y) {
x = y;
return true;
}
return false;
}
template <typename T>
bool chmax(T &x, const T &y) {
if (x < y) {
x = y;
return true;
}
return false;
}
template <typename T>
i32 lob(const V<T> &arr, const T &v) {
return (i32)(lower_bound(ALL(arr), v) - arr.begin());
}
template <typename T>
i32 upb(const V<T> &arr, const T &v) {
return (i32)(upper_bound(ALL(arr), v) - arr.begin());
}
template <typename T>
V<i32> argsort(const V<T> &arr) {
V<i32> ret(arr.size());
iota(ALL(ret), 0);
sort(ALL(ret), [&](i32 i, i32 j) -> bool {
if (arr[i] == arr[j]) {
return i < j;
} else {
return arr[i] < arr[j];
}
});
return ret;
}
#ifdef INT128
using u128 = __uint128_t;
using i128 = __int128_t;
#endif
[[maybe_unused]] constexpr i32 INF = 1000000100;
[[maybe_unused]] constexpr i64 INF64 = 3000000000000000100;
struct SetUpIO {
SetUpIO() {
#ifdef FAST_IO
ios::sync_with_stdio(false);
cin.tie(nullptr);
#endif
cout << fixed << setprecision(15);
}
} set_up_io;
void scan(char &x) { cin >> x; }
void scan(u32 &x) { cin >> x; }
void scan(u64 &x) { cin >> x; }
void scan(i32 &x) { cin >> x; }
void scan(i64 &x) { cin >> x; }
void scan(string &x) { cin >> x; }
template <typename T>
void scan(V<T> &x) {
for (T &ele : x) {
scan(ele);
}
}
void read() {}
template <typename Head, typename... Tail>
void read(Head &head, Tail &...tail) {
scan(head);
read(tail...);
}
#define CHAR(...) \
char __VA_ARGS__; \
read(__VA_ARGS__);
#define U32(...) \
u32 __VA_ARGS__; \
read(__VA_ARGS__);
#define U64(...) \
u64 __VA_ARGS__; \
read(__VA_ARGS__);
#define I32(...) \
i32 __VA_ARGS__; \
read(__VA_ARGS__);
#define I64(...) \
i64 __VA_ARGS__; \
read(__VA_ARGS__);
#define STR(...) \
string __VA_ARGS__; \
read(__VA_ARGS__);
#define VEC(type, name, size) \
V<type> name(size); \
read(name);
#define VVEC(type, name, size1, size2) \
VV<type> name(size1, V<type>(size2)); \
read(name);
// ============
#ifdef DEBUGF
#else
#define DBG(...) (void)0
#endif
// ============
#include <iostream>
#include <cassert>
#include <vector>
template <typename T>
struct Edge {
using W = T;
int from, to, id;
W weight;
Edge<T> rev() const {
return Edge<T>{to, from, id, weight};
}
};
template <typename T>
void debug(const Edge<T> &e) {
std::cerr << e.from << " -> " << e.to << " id = " << e.id << std::cerr << " weight = ";
debug(e.weight);
}
template <typename T = int, bool DIR = false>
class Graph {
public:
using E = Edge<T>;
using W = T;
static constexpr bool DIRECTED = DIR;
struct Adjacency {
using Iter = typename std::vector<E>::iterator;
Iter be, en;
Iter begin() const { return be; }
Iter end() const { return en; }
int size() const { return (int)std::distance(be, en); }
E &operator[](int idx) const { return be[idx]; }
};
struct ConstAdjacency {
using Iter = typename std::vector<E>::const_iterator;
Iter be, en;
Iter begin() const { return be; }
Iter end() const { return en; }
int size() const { return (int)std::distance(be, en); }
const E &operator[](int idx) const { return be[idx]; }
};
private:
int n, m;
std::vector<E> edges, csr;
std::vector<int> sep;
bool built;
public:
Graph(int n) : n(n), m(0), built(false) {}
int v() const { return n; }
int e() const { return m; }
int add_vertex() {
return n++;
}
void add_edge(int from, int to, W weight = 1) {
assert(0 <= from && from < n && 0 <= to && to < n);
edges.emplace_back(E{from, to, m++, weight});
}
void build() {
sep.assign(n + 1, 0);
csr.resize(DIRECTED ? m : 2 * m);
for (const E &e : edges) {
++sep[e.from + 1];
if (!DIRECTED) {
++sep[e.to + 1];
}
}
for (int i = 0; i < n; ++i) {
sep[i + 1] += sep[i];
}
std::vector<int> c = sep;
for (const E &e : edges) {
csr[c[e.from]++] = e;
if (!DIRECTED) {
csr[c[e.to]++] = e.rev();
}
}
built = true;
}
Adjacency operator[](int v) {
assert(built && 0 <= v && v < n);
return Adjacency{csr.begin() + sep[v], csr.begin() + sep[v + 1]};
}
ConstAdjacency operator[](int v) const {
assert(built && 0 <= v && v < n);
return ConstAdjacency{csr.begin() + sep[v], csr.begin() + sep[v + 1]};
}
};
// ============
void solve() {
I32(n);
Graph<> g(n);
REP(i, n - 1) {
I32(u, v);
--u;
--v;
g.add_edge(u, v);
}
g.build();
V<i32> deg(n);
REP(i, n) {
deg[i] = LEN(g[i]);
}
i64 ans = n - 1;
REP(i, n) {
ans += (i64)deg[i] * (deg[i] - 1) / 2;
}
REP(v, n) {
for (auto e : g[v]) {
if (v > e.to) {
continue;
}
ans += (i64)(deg[v] - 1) * (deg[e.to] - 1);
}
}
cout << ans << '\n';
}
int main() {
i32 t = 1;
// cin >> t;
while (t--) {
solve();
}
}
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