結果

問題 No.1075 木の上の山
ユーザー 👑 hos.lyrichos.lyric
提出日時 2020-06-05 22:22:49
言語 D
(dmd 2.109.1)
結果
AC  
実行時間 71 ms / 2,000 ms
コード長 5,294 bytes
コンパイル時間 1,749 ms
コンパイル使用メモリ 156,216 KB
実行使用メモリ 37,628 KB
最終ジャッジ日時 2024-06-22 07:17:08
合計ジャッジ時間 3,682 ms
ジャッジサーバーID
(参考情報)
judge2 / judge1
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 2
other AC * 30
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

import std.conv, std.functional, std.range, std.stdio, std.string;
import std.algorithm, std.array, std.bigint, std.bitmanip, std.complex, std.container, std.math, std.mathspecial, std.numeric, std.regex, std
    .typecons;
import core.bitop;
class EOFException : Throwable { this() { super("EOF"); } }
string[] tokens;
string readToken() { for (; tokens.empty; ) { if (stdin.eof) { throw new EOFException; } tokens = readln.split; } auto token = tokens.front; tokens
    .popFront; return token; }
int readInt() { return readToken.to!int; }
long readLong() { return readToken.to!long; }
real readReal() { return readToken.to!real; }
bool chmin(T)(ref T t, in T f) { if (t > f) { t = f; return true; } else { return false; } }
bool chmax(T)(ref T t, in T f) { if (t < f) { t = f; return true; } else { return false; } }
int binarySearch(alias pred, T)(in T[] as) { int lo = -1, hi = cast(int)(as.length); for (; lo + 1 < hi; ) { const mid = (lo + hi) >> 1;
    (unaryFun!pred(as[mid]) ? hi : lo) = mid; } return hi; }
int lowerBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a >= val)); }
int upperBound(T)(in T[] as, T val) { return as.binarySearch!(a => (a > val)); }
struct ModInt(int M_) {
import std.conv : to;
alias M = M_;
int x;
this(ModInt a) { x = a.x; }
this(long a) { x = cast(int)(a % M); if (x < 0) x += M; }
ref ModInt opAssign(long a) { return (this = ModInt(a)); }
ref ModInt opOpAssign(string op)(ModInt a) {
static if (op == "+") { x += a.x; if (x >= M) x -= M; }
else static if (op == "-") { x -= a.x; if (x < 0) x += M; }
else static if (op == "*") { x = cast(int)((cast(long)(x) * a.x) % M); }
else static if (op == "/") { this *= a.inv(); }
else static assert(false);
return this;
}
ref ModInt opOpAssign(string op)(long a) {
static if (op == "^^") {
if (a < 0) return (this = inv()^^(-a));
ModInt t2 = this, te = ModInt(1);
for (long e = a; e > 0; e >>= 1) {
if (e & 1) te *= t2;
t2 *= t2;
}
x = cast(int)(te.x);
return this;
} else return mixin("this " ~ op ~ "= ModInt(a)");
}
ModInt inv() const {
int a = x, b = M, y = 1, z = 0, t;
for (; ; ) {
t = a / b; a -= t * b;
if (a == 0) {
assert(b == 1 || b == -1);
return ModInt(b * z);
}
y -= t * z;
t = b / a; b -= t * a;
if (b == 0) {
assert(a == 1 || a == -1);
return ModInt(a * y);
}
z -= t * y;
}
}
ModInt opUnary(string op: "-")() const { return ModInt(-x); }
ModInt opBinary(string op, T)(T a) const {
return mixin("ModInt(this) " ~ op ~ "= a");
}
ModInt opBinaryRight(string op)(long a) const {
return mixin("ModInt(a) " ~ op ~ "= this");
}
bool opCast(T: bool)() const { return (x != 0); }
string toString() const { return x.to!string; }
}
enum MO = 10^^9 + 7;
alias Mint = ModInt!MO;
int N, K;
int[] A, B;
Mint[] mul(Mint[] fs, Mint[] gs) {
auto hs = new Mint[K];
foreach (k; 0 .. K) {
hs[k] = fs[k] * gs[k];
}
return hs;
}
Mint[] up(Mint[] fs) {
auto gs = fs.dup;
foreach (k; 1 .. K) {
gs[k] += gs[k - 1];
}
return gs;
}
Mint[] shift(Mint[] fs) {
return [Mint(0)] ~ fs[0 .. K - 1];
}
int[][] G;
int zeit;
int[] par, ord;
Mint[][] dp, DP;
void dfs(int u, int p) {
par[u] = p;
foreach (i; G[u]) {
const v = A[i] ^ B[i] ^ u;
if (v != p) {
dfs(v, u);
}
}
Mint[] fs = new Mint[K];
fs[] = Mint(1);
foreach (i; G[u]) {
const v = A[i] ^ B[i] ^ u;
if (v != p) {
fs = mul(fs, dp[v]);
}
}
dp[u] = up(fs);
}
void DFS(int u, int p) {
int[] vs;
foreach (i; G[u]) {
const v = A[i] ^ B[i] ^ u;
if (v != p) {
vs ~= v;
}
}
const len = cast(int)(vs.length);
auto ls = new Mint[][len + 1];
auto rs = new Mint[][len + 1];
ls[0] = new Mint[K];
ls[0][] = Mint(1);
rs[len] = new Mint[K];
rs[len][] = Mint(1);
if (p != -1) {
rs[len] = DP[u];
}
foreach (j; 0 .. len) {
ls[j + 1] = mul(ls[j], dp[vs[j]]);
}
foreach_reverse (j; 0 .. len) {
rs[j] = mul(dp[vs[j]], rs[j + 1]);
}
foreach (j; 0 .. len) {
DP[vs[j]] = up(mul(ls[j], rs[j + 1]));
}
foreach (j; 0 .. len) {
DFS(vs[j], u);
}
}
void main() {
try {
for (; ; ) {
N = readInt();
K = readInt();
A = new int[N - 1];
B = new int[N - 1];
foreach (i; 0 .. N - 1) {
A[i] = readInt() - 1;
B[i] = readInt() - 1;
}
G = new int[][N];
foreach (i; 0 .. N - 1) {
G[A[i]] ~= i;
G[B[i]] ~= i;
}
par = new int[N];
dp = new Mint[][N];
DP = new Mint[][N];
const rt = N - 1;
dfs(rt, -1);
DFS(rt, -1);
debug {
writeln("rt = ", rt);
writeln("dp = ", dp);
writeln("DP = ", DP);
}
Mint ans;
foreach (u; 0 .. N) {
Mint[] fs = new Mint[K];
fs[] = Mint(1);
if (u != rt) {
fs = shift(DP[u]);
}
foreach (i; G[u]) {
const v = A[i] ^ B[i] ^ u;
if (v != par[u]) {
fs = mul(fs, dp[v]);
}
}
debug {
writeln(u, ": ", fs);
}
ans += fs.sum;
}
writeln(ans);
}
} catch (EOFException e) {
}
}
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