結果
問題 | No.1333 Squared Sum |
ユーザー | 👑 hos.lyric |
提出日時 | 2021-01-08 21:44:53 |
言語 | D (dmd 2.109.1) |
結果 |
AC
|
実行時間 | 347 ms / 2,000 ms |
コード長 | 4,521 bytes |
コンパイル時間 | 1,690 ms |
コンパイル使用メモリ | 155,560 KB |
実行使用メモリ | 42,136 KB |
最終ジャッジ日時 | 2024-06-22 10:33:43 |
合計ジャッジ時間 | 13,393 ms |
ジャッジサーバーID (参考情報) |
judge3 / judge5 |
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ファイルパターン | 結果 |
---|---|
other | AC * 44 |
ソースコード
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;int[] A, B;long[] C;int[][] G;int[] par;int[] sz;Mint[] dp;void dfs(int u, int p) {par[u] = p;sz[u] = 1;dp[u] = 0;foreach (i; G[u]) {const v = A[i] ^ B[i] ^ u;if (v != p) {dfs(v, u);sz[u] += sz[v];dp[u] += dp[v];dp[u] += Mint(sz[v]) * Mint(C[i]);}}}void main() {try {for (; ; ) {N = readInt();A = new int[N - 1];B = new int[N - 1];C = new long[N - 1];foreach (i; 0 .. N - 1) {A[i] = readInt() - 1;B[i] = readInt() - 1;C[i] = readLong();}G = new int[][N];foreach (i; 0 .. N - 1) {G[A[i]] ~= i;G[B[i]] ~= i;}par = new int[N];sz = new int[N];dp = new Mint[N];dfs(0, -1);debug {writeln("sz = ", sz);writeln("dp = ", dp);}Mint ans;foreach (u; 0 .. N) {Mint sum;foreach (i; G[u]) {const v = A[i] ^ B[i] ^ u;if (v != par[u]) {ans += 2 * Mint(N - sz[v]) * Mint(C[i]) * dp[v];const here = dp[v] + Mint(sz[v]) * C[i];ans -= here * here;sum += here;}}ans += sum * sum;}debug {writeln("ans = ", ans);}foreach (u; 0 .. N) {Mint sum;foreach (i; G[u]) {const v = A[i] ^ B[i] ^ u;if (v != par[u]) {ans += Mint(N - sz[v]) * Mint(sz[v]) * Mint(C[i]) * Mint(C[i]);}}}writeln(ans);}} catch (EOFException e) {}}