結果
問題 | No.196 典型DP (1) |
ユーザー | paruki |
提出日時 | 2016-08-24 14:46:17 |
言語 | C++14 (gcc 13.3.0 + boost 1.87.0) |
結果 |
AC
|
実行時間 | 29 ms / 2,000 ms |
コード長 | 2,855 bytes |
コンパイル時間 | 1,771 ms |
コンパイル使用メモリ | 169,312 KB |
実行使用メモリ | 19,584 KB |
最終ジャッジ日時 | 2024-11-08 02:03:14 |
合計ジャッジ時間 | 3,537 ms |
ジャッジサーバーID (参考情報) |
judge2 / judge5 |
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ファイルパターン | 結果 |
---|---|
sample | AC * 3 |
other | AC * 41 |
ソースコード
#include "bits/stdc++.h"using namespace std;#define FOR(i,j,k) for(int (i)=(j);(i)<(int)(k);++(i))#define rep(i,j) FOR(i,0,j)#define each(x,y) for(auto &(x):(y))#define mp make_pair#define all(x) (x).begin(),(x).end()#define debug(x) cout<<#x<<": "<<(x)<<endl#define smax(x,y) (x)=max((x),(y))#define smin(x,y) (x)=min((x),(y))#define MEM(x,y) memset((x),(y),sizeof (x))#define sz(x) (int)(x).size()typedef long long ll;typedef pair<int, int> pii;typedef vector<int> vi;typedef vector<ll> vll;template<int MOD>class ModInt{public:ModInt():value(0){}ModInt(long long val):value((int)(val<0?MOD+val%MOD:val%MOD)){ }ModInt& operator+=(ModInt that){value = value+that.value;if(value>=MOD)value-=MOD;return *this;}ModInt& operator-=(ModInt that){value -= that.value;if(value<0)value+=MOD;return *this;}ModInt& operator*=(ModInt that){value = (int)((long long)value * that.value % MOD);return *this;}ModInt &operator/=(ModInt that){return *this *= that.inverse();}ModInt operator+(ModInt that) const{return ModInt(*this)+=that;}ModInt operator-(ModInt that) const{return ModInt(*this)-=that;}ModInt operator*(ModInt that) const{return ModInt(*this)*=that;}ModInt operator/(ModInt that) const {return ModInt(*this) /= that;}ModInt pow(long long k) const{if(value == 0)return 0;ModInt n = *this, res = 1;while(k){if(k & 1)res *= n;n *= n;k >>= 1;}return res;}ModInt inverse() const {long long a = value, b = MOD, u = 1, v = 0;while(b) {long long t = a / b;a -= t * b;swap(a, b);u -= t * v;swap(u, v);}return ModInt(u);}int toi() const{ return value; }private:int value;};typedef ModInt<1000000007> mint;ostream& operator<<(ostream& os, const mint& x){os << x.toi();return os;}int N, K, s[2000];vi G[2000];mint dp[2000][2001];void g(int u, int p){s[u] = 1;each(v, G[u])if(v != p){g(v, u);s[u] += s[v];}}void f(int u, int p){dp[u][0] = dp[u][s[u]] = 1;int sum = 0;each(v, G[u])if(v != p){f(v, u);for(int i = sum; i >= 0; --i){FOR(j, 1, s[v] + 1){if(i + j <= s[u]){dp[u][i+j]+=dp[u][i]*dp[v][j];}}}sum += s[v];}}int main(){int u, v;cin >> N >> K;rep(i, N-1){scanf("%d%d", &u, &v);G[u].push_back(v);G[v].push_back(u);}g(0, -1);f(0, -1);cout << dp[0][K] << endl;}