Submission #990247

#	Time	Username	Problem	Language	Result	Execution time	Memory
990247		SN0WM4N	Commuter Pass (JOI18_commuter_pass)	C++14	0 / 100	705 ms	262144 KiB

commuter_pass

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define sort undefined_function // To use stable_sort instead sort 
#define bpc __builtin_popcount
#define ull unsigned long long
#define ld double
#define ll long long
#define mp make_pair
#define F first
#define S second

#pragma GCC optimize("O3")

#ifdef LOCAL 
	#include "debug.h"
#else 
	#define dbg(...) 0
#endif

using namespace __gnu_pbds;
using namespace std;

typedef tree<long long, null_type, less_equal<long long>,
    rb_tree_tag, tree_order_statistics_node_update> Tree;

const ll INF = 9223372036854775807LL;
const ll inf = 2147483647;
const ll MOD = 1e9 + 7; //[998244353, 1e9 + 7, 1e9 + 13]
const ld PI = acos(-1);
const ll NROOT = 500;

ll binpow(ll a, ll b, ll _MOD = -1) {
	if (_MOD == -1)
		_MOD = MOD;
	ll res = 1;
	for (; b; b /= 2, a *= a, a %= _MOD)
		if (b & 1) res *= a, res %= _MOD;
	return res;
}

void set_IO(string s) {
#ifndef LOCAL
	string in  = s +  ".in";
	string out = s + ".out";
	freopen(in.c_str(),  "r",  stdin);
	freopen(out.c_str(), "w", stdout);
#endif
}

bool dataOverflow(ll a, ll b) {return (log10(a) + log10(b) >= 18);}
ll gcd(ll a, ll b) {return b ? gcd(b, a % b) : a;}
ll lcm(ll a, ll b) {return a * b / gcd(a, b);}
ll ceil(ll a, ll b) {return (a + b - 1) / b;}
ll invmod(ll a) {return binpow(a, MOD - 2);}

#define int long long

int n, m;
vector<vector<pair<int, ll>>> g;

int32_t main() {
	ios_base::sync_with_stdio(0);
	cin.tie(0); cout.tie(0);

	cin >> n >> m;
	g.resize(n + 1);
	int s, t, u, v;
	cin >> s >> t >> u >> v;
	vector<pair<pair<int, int>, ll>> edges; 
	map<pair<int, int>, int> ID, old;

	for (int i = 1; i <= m; i ++) {
		int a, b; ll c;
		cin >> a >> b >> c;

		ID[{b, a}] = ID[{a, b}] = edges.size();
		old[{b, a}] = old[{a, b}] = c;
		edges.push_back({{a, b}, c});
	
		g[a].push_back({b, c});
		g[b].push_back({a, c});
	}

	using T = pair<ll, int>;
	priority_queue<T, vector<T>, greater<T>> q;
	q.push({0, s});

	vector<ll> dis(n + 1, INF);

	while (!q.empty()) {
		auto [d, x] = q.top();
		q.pop();

		if (dis[x] <= d)
			continue;
		dis[x] = d;

		for (auto &y : g[x])
			q.push({d + y.S, y.F});
	}

	vector<bool> vis(n + 1);

	q.push({dis[t], t});
	while (!q.empty()) {
		auto [d, x] = q.top();
		q.pop();

		if (vis[x])
			continue;
		vis[x] = 1;

		for (auto &y : g[x]) {
			if (dis[y.F] + y.S == dis[x]) {
				q.push({dis[y.F], y.F});
				edges[ID[{x, y.F}]].S = 0;
			}
		}
	}

	g.clear();
	g.resize(n + 1);

	vector<vector<int>> FW(n + 1, vector<int> (n + 1, 1e16));

	for (auto &x : edges) {
		auto [a, b] = x.F;
		ll c = x.S;
	
		if (c == 0) {
			if (dis[a] < dis[b]) {
				FW[a][b] = c;
				FW[b][a] = old[{a, b}];
			}
			else {
				FW[b][a] = c;
				FW[a][b] = old[{a, b}];
			}
		} else {
			FW[a][b] = FW[b][a] = c;
		}
	}

	for (int k = 1; k <= n; k ++) {
		for (int i = 1; i <= n; i ++) {
			for (int j = 1; j <= n; j ++) {
				FW[i][j] = min(FW[i][j], FW[i][k] + FW[k][j]);
			}
		}
	}

	int ans = FW[u][v];

	FW.clear();
	FW.resize(n + 1, vector<int> (n + 1, 1e16));
	
	for (auto &x : edges) {
		auto [a, b] = x.F;
		ll c = x.S;
	
		if (c == 0) {
			if (dis[a] > dis[b]) {
				FW[a][b] = c;
				FW[b][a] = old[{a, b}];
			}
			else {
				FW[b][a] = c;
				FW[a][b] = old[{a, b}];
			}
		} else {
			FW[a][b] = FW[b][a] = c;
		}
	}

	for (int k = 1; k <= n; k ++) {
		for (int i = 1; i <= n; i ++) {
			for (int j = 1; j <= n; j ++) {
				FW[i][j] = min(FW[i][j], FW[i][k] + FW[k][j]);
			}
		}
	}

	dbg(FW[s][t]);
	cout << min(ans, FW[u][v]) << "\n";

	return 0;
}

Compilation message (stderr)

commuter_pass.cpp: In function 'int32_t main()':
commuter_pass.cpp:92:8: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   92 |   auto [d, x] = q.top();
      |        ^
commuter_pass.cpp:107:8: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  107 |   auto [d, x] = q.top();
      |        ^
commuter_pass.cpp:128:8: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  128 |   auto [a, b] = x.F;
      |        ^
commuter_pass.cpp:159:8: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  159 |   auto [a, b] = x.F;
      |        ^
commuter_pass.cpp:18:19: warning: statement has no effect [-Wunused-value]
   18 |  #define dbg(...) 0
      |                   ^
commuter_pass.cpp:184:2: note: in expansion of macro 'dbg'
  184 |  dbg(FW[s][t]);
      |  ^~~
commuter_pass.cpp: In function 'void set_IO(std::string)':
commuter_pass.cpp:46:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   46 |  freopen(in.c_str(),  "r",  stdin);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
commuter_pass.cpp:47:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   47 |  freopen(out.c_str(), "w", stdout);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 16
• Subtask 2: 0 / 15
• Subtask 3: 0 / 24
• Subtask 4: 0 / 45