結果

問題 No.916 Encounter On A Tree
ユーザー betrue12
提出日時 2019-10-25 22:13:13
言語 C++14
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 54 ms / 2,000 ms
コード長 2,232 bytes
コンパイル時間 1,742 ms
コンパイル使用メモリ 172,600 KB
実行使用メモリ 27,964 KB
最終ジャッジ日時 2024-09-13 04:07:39
合計ジャッジ時間 5,121 ms
ジャッジサーバーID
(参考情報)
judge2 / judge4
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 * 5
other AC * 56
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

#include <bits/stdc++.h>
using namespace std;
const int64_t MOD = 1e9+7;
void add(int64_t& a, int64_t b){
a = (a+b) % MOD;
}
void mul(int64_t& a, int64_t b){
a = a*b % MOD;
}
vector<int64_t> fact, seq_inv, fact_inv;
void create_fact_mod(int num){
fact[0] = fact[1] = 1;
for(int i=2; i<=num; i++) fact[i] = fact[i-1] * i % MOD;
}
void create_seq_inv_mod(int num){
seq_inv[0] = seq_inv[1] = 1;
for(int i=2; i<=num; i++) seq_inv[i] = (MOD - MOD/i) * seq_inv[MOD%i] % MOD;
}
void create_fact_inv_mod(int num){
fact_inv[0] = fact_inv[1] = 1;
for(int i=2; i<=num; i++) fact_inv[i] = fact_inv[i-1] * seq_inv[i] % MOD;
}
void create_mod_tables(int num){
fact.resize(num+1);
seq_inv.resize(num+1);
fact_inv.resize(num+1);
create_fact_mod(num);
create_seq_inv_mod(num);
create_fact_inv_mod(num);
}
int64_t comb_mod(int n, int k){
return fact[n] * fact_inv[n-k] % MOD * fact_inv[k] % MOD;
}
int64_t perm_mod(int n, int k){
return fact[n] * fact_inv[n-k] % MOD;
}
int64_t power_mod(int64_t num, int64_t power){
int64_t prod = 1;
num %= MOD;
while(power > 0){
if(power&1) prod = prod * num % MOD;
num = num * num % MOD;
power >>= 1;
}
return prod;
}
int64_t extgcd(int64_t a, int64_t b, int64_t& x, int64_t& y){
int64_t d = a;
if(b != 0){
d = extgcd(b, a%b, y, x);
y -= (a/b) * x;
}else{
x = 1; y = 0;
}
return d;
}
int64_t inv_mod(int64_t a){
int64_t x, y;
extgcd(a, MOD, x, y);
return (MOD + x%MOD) % MOD;
}
void fail(){
cout << 0 << endl;
exit(0);
}
int main(){
int D, L, R, K;
cin >> D >> L >> R >> K;
int ld = 1, rd = 1;
while((1<<ld) <= L) ld++;
while((1<<rd) <= R) rd++;
int rest = K - (rd-ld);
if(rest%2) fail();
if(rest < 0) fail();
int lca = ld - rest/2;
if(lca <= 0) fail();
int64_t ans = 1<<(lca-1);
mul(ans, 2);
if(lca < ld) mul(ans, 1<<(ld-lca-1));
mul(ans, 1<<(rd-lca-1));
create_mod_tables(1<<20);
for(int d=1; d<=D; d++){
int num = 1<<(d-1);
if(d==ld) num--;
if(d==rd) num--;
mul(ans, fact[num]);
}
cout << ans << endl;
return 0;
}
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