Submission #8172122


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// need
#include <iostream>
#include <algorithm>
// data structure
#include <bitset>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <utility>
#include <vector>
#include <complex>
//#include <deque>
#include <valarray>
#include <unordered_map>
#include <unordered_set>
#include <array>
// etc
#include <cassert>
#include <cmath>
#include <functional>
#include <iomanip>
#include <chrono>
#include <random>
#include <numeric>
#include <fstream>

// input
#define INIT std::ios::sync_with_stdio(false);std::cin.tie(0);
#define VAR(type, ...)type __VA_ARGS__;MACRO_VAR_Scan(__VA_ARGS__);
template<typename T> void MACRO_VAR_Scan(T& t) { std::cin >> t; }
template<typename First, typename...Rest>void MACRO_VAR_Scan(First& first, Rest& ...rest) { std::cin >> first; MACRO_VAR_Scan(rest...); }
#define VEC_ROW(type, n, ...)std::vector<type> __VA_ARGS__;MACRO_VEC_ROW_Init(n, __VA_ARGS__); for(int w_=0; w_<n; ++w_){MACRO_VEC_ROW_Scan(w_, __VA_ARGS__);}
template<typename T> void MACRO_VEC_ROW_Init(int n, T& t) { t.resize(n); }
template<typename First, typename...Rest>void MACRO_VEC_ROW_Init(int n, First& first, Rest& ...rest) { first.resize(n); MACRO_VEC_ROW_Init(n, rest...); }
template<typename T> void MACRO_VEC_ROW_Scan(int p, T& t) { std::cin >> t[p]; }
template<typename First, typename...Rest>void MACRO_VEC_ROW_Scan(int p, First& first, Rest& ...rest) { std::cin >> first[p]; MACRO_VEC_ROW_Scan(p, rest...); }
#define VEC(type, c, n) std::vector<type> c(n);for(auto& i:c)std::cin>>i;
#define MAT(type, c, m, n) std::vector<std::vector<type>> c(m, std::vector<type>(n));for(auto& R:c)for(auto& w:R)std::cin>>w;
// output
template<typename T>void MACRO_OUT(const T t) { std::cout << t; }
template<typename First, typename...Rest>void MACRO_OUT(const First first, const Rest...rest) { std::cout << first << " "; MACRO_OUT(rest...); }
#define OUT(...) MACRO_OUT(__VA_ARGS__);
#define FOUT(n, dist) std::cout<<std::fixed<<std::setprecision(n)<<(dist);
#define SOUT(n, c, dist) std::cout<<std::setw(n)<<std::setfill(c)<<(dist);
#define SP std::cout<<" ";
#define TAB std::cout<<"\t";
#define BR std::cout<<"\n";
#define SPBR(w, n) std::cout<<(w + 1 == n ? '\n' : ' ');
#define ENDL std::cout<<std::endl;
#define FLUSH std::cout<<std::flush;
#define SHOW(dist) {std::cerr << #dist << "\t: " << (dist) << "\n";}
#define SHOWVECTOR(v) {std::cerr << #v << "\t: ";for(const auto& xxx : v){std::cerr << xxx << " ";}std::cerr << "\n";}
#define SHOWVECTOR2(v) {std::cerr << #v << "\t:\n";for(const auto& xxx : v){for(const auto& yyy : xxx){std::cerr << yyy << " ";}std::cerr << "\n";}}
#define SHOWQUEUE(a) {auto tmp(a);std::cerr << #a << "\t: ";while(!tmp.empty()){std::cerr << tmp.front() << " ";tmp.pop();}std::cerr << "\n";}
#define SHOWSTACK(a) {auto tmp(a);std::cerr << #a << "\t: ";while(!tmp.empty()){std::cerr << tmp.top() << " ";tmp.pop();}std::cerr << "\n";}
// utility
#define ALL(a) (a).begin(),(a).end()
#define FOR(w, a, n) for(int w=(a);w<(n);++w)
#define RFOR(w, a, n) for(int w=(n)-1;w>=(a);--w)
#define REP(w, n) for(int w=0;w<int(n);++w)
#define RREP(w, n) for(int w=int(n)-1;w>=0;--w)
#define IN(a, x, b) (a<=x && x<b)
template<class T> inline T CHMAX(T & a, const T b) { return a = (a < b) ? b : a; }
template<class T> inline T CHMIN(T& a, const T b) { return a = (a > b) ? b : a; }
// test
template<class T> using V = std::vector<T>;
template<class T> using VV = V<V<T>>;

template<typename S, typename T>
std::ostream& operator<<(std::ostream& os, std::pair<S, T> p) {
	os << "(" << p.first << ", " << p.second << ")"; return os;
}

// type/const
#define int ll
using ll = long long;
using ull = unsigned long long;
using ld = long double;
using PAIR = std::pair<int, int>;
using PAIRLL = std::pair<ll, ll>;
constexpr int INFINT = (1 << 30) - 1;                    // 1.07x10^ 9
constexpr int INFINT_LIM = (1LL << 31) - 1;              // 2.15x10^ 9
constexpr ll INFLL = 1LL << 60;                          // 1.15x10^18
constexpr ll INFLL_LIM = (1LL << 62) - 1 + (1LL << 62);  // 9.22x10^18
constexpr double EPS = 1e-10;
constexpr int MOD = 1000000007;
constexpr double PI = 3.141592653589793238462643383279;
template<class T, size_t N> void FILL(T(&a)[N], const T & val) { for (auto& x : a) x = val; }
template<class ARY, size_t N, size_t M, class T> void FILL(ARY(&a)[N][M], const T & val) { for (auto& b : a) FILL(b, val); }
template<class T> void FILL(std::vector<T> & a, const T & val) { for (auto& x : a) x = val; }
template<class ARY, class T> void FILL(std::vector<std::vector<ARY>> & a, const T & val) { for (auto& b : a) FILL(b, val); }
// ------------>8------------------------------------->8------------

double dp[602];

signed main() {
	INIT;

	VAR(int, n, m);
	VEC_ROW(int, m, a, b);
	std::vector<std::vector<int>> g(n);
	REP(i, m) {
		--a[i]; --b[i];
		g[a[i]].emplace_back(b[i]);
	}

	double ans = 1e300;
	auto run = [&](int end) {
		RREP(i, n) {
			if (i == n - 1) {
				dp[i] = 0;
			}
			else {
				if (i + 1 == end) {
					if (g[i].size() >= 2) {
						double ma = 0;
						for (auto& to : g[i]) CHMAX(ma, dp[to]);

						dp[i] = 1;
						for (auto& to : g[i]) dp[i] += dp[to] / (g[i].size() - 1);
						dp[i] -= ma / (g[i].size() - 1);
					}
					else {
						dp[i] = dp[g[i][0]] + 1;
					}
				}
				else {
					dp[i] = 1;
					for (auto& to : g[i]) dp[i] += dp[to] / g[i].size();
				}
			}
		}
		CHMIN(ans, dp[0]);
	};
	RREP(i, n) run(i + 1);
	FOUT(12, ans)BR;

	return 0;
}

Submission Info

Submission Time
Task F - Fork in the Road
User satanic0258
Language C++14 (GCC 5.4.1)
Score 600
Code Size 5601 Byte
Status AC
Exec Time 518 ms
Memory 5376 KB

Judge Result

Set Name Sample All
Score / Max Score 0 / 0 600 / 600
Status
AC × 3
AC × 65
Set Name Test Cases
Sample 00-sample-00, 00-sample-01, 00-sample-02
All 00-sample-00, 00-sample-01, 00-sample-02, 01-handmade-03, 01-handmade-04, 01-handmade-05, 01-handmade-06, 01-handmade-07, 01-handmade-08, 01-handmade-09, 02-small-10, 02-small-11, 02-small-12, 02-small-13, 02-small-14, 02-small-15, 02-small-16, 02-small-17, 02-small-18, 02-small-19, 02-small-20, 02-small-21, 02-small-22, 02-small-23, 02-small-24, 03-medium-25, 03-medium-26, 03-medium-27, 03-medium-28, 03-medium-29, 03-medium-30, 03-medium-31, 03-medium-32, 03-medium-33, 03-medium-34, 03-medium-35, 03-medium-36, 03-medium-37, 03-medium-38, 03-medium-39, 03-medium-40, 03-medium-41, 03-medium-42, 03-medium-43, 03-medium-44, 04-large-45, 04-large-46, 04-large-47, 04-large-48, 04-large-49, 04-large-50, 04-large-51, 04-large-52, 04-large-53, 04-large-54, 04-large-55, 04-large-56, 04-large-57, 04-large-58, 04-large-59, 04-large-60, 04-large-61, 04-large-62, 04-large-63, 04-large-64
Case Name Status Exec Time Memory
00-sample-00 AC 1 ms 256 KB
00-sample-01 AC 1 ms 256 KB
00-sample-02 AC 1 ms 256 KB
01-handmade-03 AC 518 ms 5376 KB
01-handmade-04 AC 518 ms 5376 KB
01-handmade-05 AC 1 ms 256 KB
01-handmade-06 AC 507 ms 5248 KB
01-handmade-07 AC 4 ms 384 KB
01-handmade-08 AC 141 ms 1664 KB
01-handmade-09 AC 1 ms 256 KB
02-small-10 AC 1 ms 256 KB
02-small-11 AC 1 ms 256 KB
02-small-12 AC 1 ms 256 KB
02-small-13 AC 1 ms 256 KB
02-small-14 AC 1 ms 256 KB
02-small-15 AC 1 ms 256 KB
02-small-16 AC 1 ms 256 KB
02-small-17 AC 1 ms 256 KB
02-small-18 AC 1 ms 256 KB
02-small-19 AC 1 ms 256 KB
02-small-20 AC 1 ms 256 KB
02-small-21 AC 1 ms 256 KB
02-small-22 AC 1 ms 256 KB
02-small-23 AC 1 ms 256 KB
02-small-24 AC 1 ms 256 KB
03-medium-25 AC 1 ms 256 KB
03-medium-26 AC 2 ms 256 KB
03-medium-27 AC 1 ms 256 KB
03-medium-28 AC 2 ms 256 KB
03-medium-29 AC 2 ms 384 KB
03-medium-30 AC 1 ms 256 KB
03-medium-31 AC 1 ms 256 KB
03-medium-32 AC 2 ms 256 KB
03-medium-33 AC 2 ms 256 KB
03-medium-34 AC 2 ms 384 KB
03-medium-35 AC 1 ms 256 KB
03-medium-36 AC 2 ms 256 KB
03-medium-37 AC 2 ms 384 KB
03-medium-38 AC 2 ms 256 KB
03-medium-39 AC 1 ms 256 KB
03-medium-40 AC 1 ms 256 KB
03-medium-41 AC 1 ms 256 KB
03-medium-42 AC 2 ms 384 KB
03-medium-43 AC 2 ms 256 KB
03-medium-44 AC 2 ms 256 KB
04-large-45 AC 5 ms 384 KB
04-large-46 AC 18 ms 512 KB
04-large-47 AC 71 ms 1024 KB
04-large-48 AC 124 ms 1536 KB
04-large-49 AC 201 ms 2304 KB
04-large-50 AC 5 ms 384 KB
04-large-51 AC 17 ms 512 KB
04-large-52 AC 77 ms 1024 KB
04-large-53 AC 140 ms 1664 KB
04-large-54 AC 255 ms 2688 KB
04-large-55 AC 5 ms 384 KB
04-large-56 AC 18 ms 512 KB
04-large-57 AC 71 ms 1024 KB
04-large-58 AC 125 ms 1536 KB
04-large-59 AC 198 ms 2304 KB
04-large-60 AC 5 ms 384 KB
04-large-61 AC 18 ms 512 KB
04-large-62 AC 78 ms 1024 KB
04-large-63 AC 153 ms 1792 KB
04-large-64 AC 269 ms 2816 KB