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QOJ
ID | 题目 | 提交者 | 结果 | 用时 | 内存 | 语言 | 文件大小 | 提交时间 | 测评时间 |
---|---|---|---|---|---|---|---|---|---|
#706398 | #9530. A Game On Tree | youthpaul | WA | 185ms | 18812kb | C++20 | 4.4kb | 2024-11-03 11:05:46 | 2024-11-03 11:05:48 |
Judging History
answer
#include<bits/stdc++.h>
#define fore(i,l,r) for(int i=(int)(l);i<(int)(r);++i)
#define fi first
#define se second
#define endl '\n'
#define ull unsigned long long
#define ALL(v) v.begin(), v.end()
#define Debug(x, ed) std::cerr << #x << " = " << x << ed;
const int INF=0x3f3f3f3f;
const long long INFLL=1e18;
typedef long long ll;
template<class T>
constexpr T power(T a, ll b){
T res = 1;
while(b){
if(b&1) res = res * a;
a = a * a;
b >>= 1;
}
return res;
}
constexpr ll mul(ll a,ll b,ll mod){ //快速乘,避免两个long long相乘取模溢出
ll res = a * b - ll(1.L * a * b / mod) * mod;
res %= mod;
if(res < 0) res += mod; //误差
return res;
}
template<ll P>
struct MLL{
ll x;
constexpr MLL() = default;
constexpr MLL(ll x) : x(norm(x % getMod())) {}
static ll Mod;
constexpr static ll getMod(){
if(P > 0) return P;
return Mod;
}
constexpr static void setMod(int _Mod){
Mod = _Mod;
}
constexpr ll norm(ll x) const{
if(x < 0){
x += getMod();
}
if(x >= getMod()){
x -= getMod();
}
return x;
}
constexpr ll val() const{
return x;
}
explicit constexpr operator ll() const{
return x; //将结构体显示转换为ll类型: ll res = static_cast<ll>(OBJ)
}
constexpr MLL operator -() const{ //负号,等价于加上Mod
MLL res;
res.x = norm(getMod() - x);
return res;
}
constexpr MLL inv() const{
assert(x != 0);
return power(*this, getMod() - 2); //用费马小定理求逆
}
constexpr MLL& operator *= (MLL rhs) & { //& 表示“this”指针不能指向一个临时对象或const对象
x = mul(x, rhs.x, getMod()); //该函数只能被一个左值调用
return *this;
}
constexpr MLL& operator += (MLL rhs) & {
x = norm(x + rhs.x);
return *this;
}
constexpr MLL& operator -= (MLL rhs) & {
x = norm(x - rhs.x);
return *this;
}
constexpr MLL& operator /= (MLL rhs) & {
return *this *= rhs.inv();
}
friend constexpr MLL operator * (MLL lhs, MLL rhs){
MLL res = lhs;
res *= rhs;
return res;
}
friend constexpr MLL operator + (MLL lhs, MLL rhs){
MLL res = lhs;
res += rhs;
return res;
}
friend constexpr MLL operator - (MLL lhs, MLL rhs){
MLL res = lhs;
res -= rhs;
return res;
}
friend constexpr MLL operator / (MLL lhs, MLL rhs){
MLL res = lhs;
res /= rhs;
return res;
}
friend constexpr std::istream& operator >> (std::istream& is, MLL& a){
ll v;
is >> v;
a = MLL(v);
return is;
}
friend constexpr std::ostream& operator << (std::ostream& os, MLL& a){
return os << a.val();
}
friend constexpr bool operator == (MLL lhs, MLL rhs){
return lhs.val() == rhs.val();
}
friend constexpr bool operator != (MLL lhs, MLL rhs){
return lhs.val() != rhs.val();
}
};
const ll mod = 998244353;
using Z = MLL<mod>;
template<>
ll MLL<0ll>::Mod = 998244353;
//using Z = MLL<0ll>;
const int N = 100005;
std::vector<int> g[N];
ll sz[N];
ll sum[N];
ll s;
int n;
void dfs(int u, int f){
sz[u] = 1;
sum[u] = 0;
ll s0 = 0;
for(auto v : g[u])
if(v != f){
dfs(v, u);
sz[u] += sz[v];
sum[u] += sum[v];
s += 2 * (n - sz[v]) * (n - sz[v]) * (sum[v] - sz[v] * sz[v]); //contri 2.1
s += 2 * s0 * sum[v]; //contri 2.2
s0 += sum[v];
}
sum[u] += sz[u] * sz[u];
s += sz[u] * sz[u] * (n - sz[u]) * (n - sz[u]); //contri 1
}
int main(){
std::ios::sync_with_stdio(false);
std::cin.tie(nullptr);
std::cout.tie(nullptr);
int t;
std::cin >> t;
while(t--){
std::cin >> n;
fore(i, 1, n){
int u, v;
std::cin >> u >> v;
g[u].push_back(v);
g[v].push_back(u);
}
s = 0;
dfs(1, 0);
Z p = Z(n) * (n - 1) / 2;
p *= p;
Z ans = s / p;
std::cout << ans << endl;
fore(i, 1, n + 1) g[i].clear();
}
return 0;
}
详细
Test #1:
score: 100
Accepted
time: 1ms
memory: 3560kb
input:
2 3 1 2 2 3 5 1 2 1 5 3 2 4 2
output:
443664158 918384806
result:
ok 2 lines
Test #2:
score: 0
Accepted
time: 2ms
memory: 3588kb
input:
1000 7 3 6 4 3 5 3 2 6 1 4 7 1 12 5 7 10 7 2 10 11 2 1 7 8 1 4 2 9 11 6 9 12 11 3 5 6 2 5 1 2 4 5 6 4 3 6 5 2 5 1 5 4 5 3 2 8 1 8 2 8 4 2 6 1 5 6 7 6 3 8 8 3 8 7 3 4 8 6 4 2 7 5 2 1 4 4 3 1 4 3 2 1 6 5 1 6 1 2 5 3 5 4 2 12 8 11 5 11 12 8 3 12 6 12 2 3 4 6 10 11 1 5 9 5 7 5 9 6 1 7 6 4 7 8 7 5 4 9 6 ...
output:
948445317 468414020 550143557 918384806 711758412 487662742 776412276 869581749 240852807 765628773 211048577 887328316 890334966 940494682 760637552 908032643 592850815 584006902 908525604 221832080 433351719 56023919 867301808 183319566 698771049 366957926 449579681 599710576 310564911 286902823 3...
result:
ok 1000 lines
Test #3:
score: 0
Accepted
time: 4ms
memory: 3672kb
input:
1000 94 59 1 33 59 73 1 6 33 83 59 4 59 20 59 61 6 39 1 76 73 71 6 44 39 9 71 24 4 87 9 57 83 2 9 81 71 82 20 90 2 85 39 12 9 30 83 66 30 53 9 47 9 36 44 43 53 29 12 31 53 64 81 38 31 84 82 77 38 23 71 93 84 78 83 58 31 68 90 42 1 55 64 13 78 70 78 62 24 19 55 92 87 14 57 10 84 65 81 63 6 75 36 91 1...
output:
508107725 996793960 201633249 335988372 842755864 460619380 342223697 207523414 429241811 391691799 542977964 786416604 454278948 685531402 25914978 440729774 228518323 679471537 82764520 554190841 432505337 143444089 189106586 337234245 61954935 905141094 532919674 703954588 185671863 942858630 692...
result:
ok 1000 lines
Test #4:
score: -100
Wrong Answer
time: 185ms
memory: 18812kb
input:
10000 8 1 4 3 1 5 1 7 3 8 4 6 8 2 7 8 2 6 4 6 5 6 8 5 7 6 3 5 1 7 8 8 5 6 5 2 5 7 2 1 6 3 1 4 8 9 8 6 9 8 3 6 1 8 5 9 2 8 4 3 7 9 8 8 6 3 6 5 8 1 6 4 3 7 6 2 6 9 9 5 7 5 2 7 8 7 4 9 3 7 6 3 1 4 8 1 4 5 1 6 5 3 4 8 4 7 8 2 5 9 1 8 6 1 2 1 3 8 5 3 9 8 7 8 4 8 9 4 9 2 9 1 2 3 4 5 2 6 9 8 3 7 2 8 1 2 8 ...
output:
49657566 56023919 387074343 97051536 701572244 211048577 711758412 308100110 761007271 711758412 178698065 285212675 80216065 43380497 267677376 818005792 53239701 765628773 970145625 387074343 436731906 422725927 479157293 977872021 436731906 925779210 487662742 705549251 267677376 711758412 526851...
result:
wrong answer 9992nd lines differ - expected: '391800050', found: '936887512'