Submission #781223

#	Time	Username	Problem	Language	Result	Execution time	Memory
781223		GusterGoose27	Toy Train (IOI17_train)	C++17	100 / 100	349 ms	1860 KiB

train

#include "train.h"

#include <bits/stdc++.h>

const int MAXN = 5005;
using namespace std;
vector<int> edges[MAXN];
vector<int> rev[MAXN];
int deg[MAXN];
bool owner[MAXN]; // 0 b, 1 a
vector<int> ans;
int n, m;

void activate(int cur) {
	if (ans[cur]) return; // r[i]
	assert(!ans[cur]);
	ans[cur] = 1;
	for (int v: rev[cur]) {
		deg[v]++;
		if ((deg[v] == 1 && owner[v]) || (deg[v] == edges[v].size() && !owner[v])) activate(v);
	}
}

void deactivate(int cur) {
	assert(ans[cur]);
	ans[cur] = 0;
	for (int v: rev[cur]) {
		deg[v]--;
		if ((deg[v] == 0 && owner[v]) || (deg[v] == edges[v].size()-1 && !owner[v])) deactivate(v);
	}
}

vector<int> who_wins(vector<int> a, vector<int> r, vector<int> u, vector<int> v) {
	n = a.size();
	m = u.size();
	for (int i = 0; i < n; i++) owner[i] = a[i];
	for (int i = 0; i < m; i++) {
		edges[u[i]].push_back(v[i]);
		rev[v[i]].push_back(u[i]);
	}
	bool f = 1;
	while (f) {
		f = 0;
		fill(deg, deg+n, 0);
		ans = vector<int>(n, 0);
		for (int i = 0; i < n; i++) {
			if (r[i]) activate(i);
		}
		for (int i = 0; i < n; i++) {
			if (ans[i] && ((deg[i] == 0 && owner[i]) || (deg[i] < edges[i].size() && !owner[i]))) {
				r[i] = 0;
				f = 1;
				break;
			}
		}
	}
	return ans;
}

Compilation message (stderr)

train.cpp: In function 'void activate(int)':
train.cpp:20:44: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   20 |   if ((deg[v] == 1 && owner[v]) || (deg[v] == edges[v].size() && !owner[v])) activate(v);
      |                                     ~~~~~~~^~~~~~~~~~~~~~~~~~
train.cpp: In function 'void deactivate(int)':
train.cpp:29:44: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   29 |   if ((deg[v] == 0 && owner[v]) || (deg[v] == edges[v].size()-1 && !owner[v])) deactivate(v);
      |                                     ~~~~~~~^~~~~~~~~~~~~~~~~~~~
train.cpp: In function 'std::vector<int> who_wins(std::vector<int>, std::vector<int>, std::vector<int>, std::vector<int>)':
train.cpp:50:56: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   50 |    if (ans[i] && ((deg[i] == 0 && owner[i]) || (deg[i] < edges[i].size() && !owner[i]))) {
      |                                                 ~~~~~~~^~~~~~~~~~~~~~~~~

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