結果
問題 | No.1075 木の上の山 |
ユーザー |
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提出日時 | 2020-07-22 22:18:47 |
言語 | C++11 (gcc 13.3.0) |
結果 |
AC
|
実行時間 | 229 ms / 2,000 ms |
コード長 | 4,308 bytes |
コンパイル時間 | 1,337 ms |
コンパイル使用メモリ | 105,216 KB |
実行使用メモリ | 35,408 KB |
最終ジャッジ日時 | 2024-06-22 18:47:43 |
合計ジャッジ時間 | 4,846 ms |
ジャッジサーバーID (参考情報) |
judge2 / judge1 |
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ファイルパターン | 結果 |
---|---|
sample | AC * 2 |
other | AC * 30 |
ソースコード
#include<iostream>#include<string>#include<cstdio>#include<vector>#include<cmath>#include<algorithm>#include<functional>#include<iomanip>#include<queue>#include<ciso646>#include<random>#include<map>#include<set>#include<complex>#include<bitset>#include<stack>#include<unordered_map>#include<utility>#include<tuple>using namespace std;typedef long long ll;typedef unsigned int ui;const ll mod = 1000000007;const ll INF = (ll)1000000007 * 1000000007;typedef pair<int, int> P;#define stop char nyaa;cin>>nyaa;#define rep(i,n) for(int i=0;i<n;i++)#define per(i,n) for(int i=n-1;i>=0;i--)#define Rep(i,sta,n) for(int i=sta;i<n;i++)#define Per(i,sta,n) for(int i=n-1;i>=sta;i--)#define rep1(i,n) for(int i=1;i<=n;i++)#define per1(i,n) for(int i=n;i>=1;i--)#define Rep1(i,sta,n) for(int i=sta;i<=n;i++)typedef long double ld;const ld eps = 1e-8;const ld pi = acos(-1.0);typedef pair<ll, ll> LP;int dx[4]={1,-1,0,0};int dy[4]={0,0,1,-1};template<int mod>struct ModInt {long long x;ModInt() : x(0) {}ModInt(long long y) : x(y >= 0 ? y % mod : (mod - (-y) % mod) % mod) {}explicit operator int() const {return x;}ModInt &operator+=(const ModInt &p) {if((x += p.x) >= mod) x -= mod;return *this;}ModInt &operator-=(const ModInt &p) {if((x += mod - p.x) >= mod) x -= mod;return *this;}ModInt &operator*=(const ModInt &p) {x = (int)(1LL * x * p.x % mod);return *this;}ModInt &operator/=(const ModInt &p) {*this *= p.inverse();return *this;}ModInt operator-() const { return ModInt(-x); }ModInt operator+(const ModInt &p) const { return ModInt(*this) += p; }ModInt operator-(const ModInt &p) const { return ModInt(*this) -= p; }ModInt operator*(const ModInt &p) const { return ModInt(*this) *= p; }ModInt operator/(const ModInt &p) const { return ModInt(*this) /= p; }bool operator==(const ModInt &p) const { return x == p.x; }bool operator!=(const ModInt &p) const { return x != p.x; }ModInt inverse() const{int a = x, b = mod, u = 1, v = 0, t;while(b > 0) {t = a / b;a -= t * b;swap(a, b);u -= t * v;swap(u, v);}return ModInt(u);}ModInt power(long long p) const{int a = x;if (p==0) return 1;if (p==1) return ModInt(a);if (p%2==1) return (ModInt(a)*ModInt(a)).power(p/2)*ModInt(a);else return (ModInt(a)*ModInt(a)).power(p/2);}ModInt power(const ModInt p) const{return ((ModInt)x).power(p.x);}friend ostream &operator<<(ostream &os, const ModInt<mod> &p) {return os << p.x;}friend istream &operator>>(istream &is, ModInt<mod> &a) {long long x;is >> x;a = ModInt<mod>(x);return (is);}};using modint = ModInt<mod>;int n,k;modint dp[1010][1010],dpS[1010][1010];modint dp2[1010][1010],dpS2[1010][1010];modint ans;vector<int> G[1010];void dfs(int s,int par){Rep(j,1,k+1){dp[s][j]=1;}for(int t:G[s]){if(t==par) continue;dfs(t,s);Rep(j,1,k+1){dp[s][j]*=dpS[t][j];}}rep(j,k){dpS[s][j+1]=dpS[s][j]+dp[s][j+1];}}void dfs2(int s,int par){//cout << s << endl;if(s!=0) {Rep(j,1,k+1) {dp2[s][j]=dp[s][j]*dpS2[s][j];ans+=dp[s][j]*dpS2[s][j-1];//cout << s << " " << ans << endl;}}else Rep(j,1,k+1) {dp2[s][j]=dp[s][j];ans+=dp[s][j];//cout << s << " " << ans << endl;}for(int t:G[s]){if(t==par) continue;rep(j,k){dpS2[t][j+1]=dpS2[t][j]+dp2[s][j+1]/dpS[t][j+1];}dfs2(t,s);}}void solve(){cin >> n >> k;rep(i,n-1){int a,b;cin >> a >> b;a--;b--;G[a].push_back(b);G[b].push_back(a);}dfs(0,-1);// rep(i,n){// Rep(j,1,k+1){// cout << i << " " << j << " " << dp[i][j] << endl;// }// }dfs2(0,-1);// rep(i,n){// Rep(j,1,k+1){// cout << i << " " << j << " " << dpS2[i][j] << endl;// }// }cout << ans << endl;}int main(){ios::sync_with_stdio(false);cin.tie(0);cout << fixed << setprecision(50);solve();}