Submission #406949

#	Time	Username	Problem	Language	Result	Execution time	Memory
406949		Kevin_Zhang_TW	Toy Train (IOI17_train)	C++17	5 / 100	1399 ms	262148 KiB

train

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define pb emplace_back
#define AI(i) begin(i), end(i)
template<class T> bool chmin(T &a, T b) { return b < a && (a = b, true); }
template<class T> bool chmax(T &a, T b) { return a < b && (a = b, true); }
#ifdef KEV
#define DE(args...) kout("[ " + string(#args) + " ] = ", args)
void kout() { cerr << endl; }
template<class T, class ...U> void kout(T a, U ...b) { cerr << a << ' ', kout(b...); }
template<class T> void debug(T l, T r) { while (l != r) cerr << *l << " \n"[next(l)==r], ++l; }
#else
#define DE(...) 0
#define debug(...) 0
#endif

const int MAX_N = 300010;

#include "train.h"

int dp[MAX_N], w[MAX_N], sum[MAX_N], inst[MAX_N], n;
int belong[MAX_N];
vector<int> edge[MAX_N];

bool dfs(int x, int s, int v = 0) {
	static vector<int> stk, allstk;
	if (dp[x] != -1) return dp[x] == s;

	stk.pb(x);
	allstk.pb(x);
	inst[x] = true;
	v += w[x];
	sum[x] = v;

	bool ret = true, ch = false;

	// A owns it
	if (belong[x] == 1) {
		dp[x] = 0;
		for (int u : edge[x]) {
			if (dp[u] != -1 && inst[u]) {
				if (w[u] || sum[x] != sum[u]) {
					dp[x] = 1;
					break;
				}
			}
			if (inst[u]) continue;
			if (dfs(u, 1, v)) {
				dp[x] = 1;
				break;
			}
		}
		if (dp[x]) ch = true;
		if (dp[x] != s) {
			ret = false;
			dp[x] = -1;
		}
	}
	else {
		dp[x] = 1;
		for (int u : edge[x]) {
			if (dp[u] != -1 && inst[u]) {
				if (w[u] == 0 && sum[x] == sum[u]) {
					dp[x] = 0;
					break;
				}
			}
			if (inst[u]) continue;
			if (dfs(u, 0, v)) {
				DE(u, 0);
				dp[x] = 0;
				break;
			}
		}
		if (dp[x] == 0) ch = true;
		if (dp[x] != s) {
			ret = false;
			dp[x] = -1;
		}
	}

	if (ch) {
		int u;
		do {
			u = allstk.back();
			dp[x] = -1;
			allstk.pop_back();
		} while (u != x) ;
	}
	
	stk.pop_back();
	inst[x] = false;

	return ret;
}

std::vector<int> who_wins(std::vector<int> a, std::vector<int> r, std::vector<int> u, std::vector<int> v) {
	n = a.size();
	for (int i = 0;i < n;++i) {
		w[i] = r[i];
		belong[i] = a[i];
	}
	for (int i = 0;i < u.size();++i) {
		edge[ u[i] ].pb( v[i] );
	}

	memset(dp, -1, sizeof(dp));

	vector<int> res(n);
	for (int i = 0;i < n;++i) {
		res[i] = dfs(i, 1);
	}

	return res;
}

Compilation message (stderr)

train.cpp: In function 'bool dfs(int, int, int)':
train.cpp:14:17: warning: statement has no effect [-Wunused-value]
   14 | #define DE(...) 0
      |                 ^
train.cpp:71:5: note: in expansion of macro 'DE'
   71 |     DE(u, 0);
      |     ^~
train.cpp: In function 'std::vector<int> who_wins(std::vector<int>, std::vector<int>, std::vector<int>, std::vector<int>)':
train.cpp:104:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  104 |  for (int i = 0;i < u.size();++i) {
      |                 ~~^~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 0 / 10
• Subtask 3: 0 / 11
• Subtask 4: 0 / 11
• Subtask 5: 0 / 12
• Subtask 6: 0 / 51