Submission #70130

#	Time	Username	Problem	Language	Result	Execution time	Memory
70130		bnahmad15	Toy Train (IOI17_train)	C++17	15 / 100	1266 ms	2992 KiB

train

#include "train.h"
#include <bits/stdc++.h>
using namespace std;

const int N = 5001;
int n,is[N],vis[N],own[N],to[N],self[N],flag1 = 1,flag2 = 1,no[N],tim[N],cnt = 0,can[N];
vector <int> g[N],S;

int dfs(int u){
	vis[u] = 1;
	S.push_back(u);
	int ret;
	if(own[u] == 0){
		ret = 1;
		for(int i = 0;i<g[u].size();i++){
			int v = g[u][i];
			if(vis[v] == 1){
				int flag = 0;
				for(int j = S.size()-1;j>=0;j--){
					if(is[S[j]] == 1){
						flag = 1;
						break;
					}
					if(S[j] == v)
						break;
				}
				ret = min(ret,flag);
			}else{
				ret = min(ret,dfs(v));
			}
		}
	}else{
		ret = 0;
		for(int i = 0;i<g[u].size();i++){
			int v = g[u][i];
			if(vis[v] == 1){
				int flag = 0;
				for(int j = S.size()-1;j>=0;j--){
					if(is[S[j]] == 1){
						flag = 1;
						break;
					}
					if(S[j] == v)
						break;
				}
				ret = max(ret,flag);
			}else{
				ret = max(ret,dfs(v));
			}
		}
	}
	vis[u] = 0;
	S.pop_back();
	return ret;
}

int DFS(int u,int found){
	tim[u] = ++cnt;
	vis[u] = 1;
	no[tim[u]] = 1;
	int res = 0;
	if(is[u] == 1)
		found = tim[u];
	for(int i = 0;i<g[u].size();i++){
		int v = g[u][i];
		if(vis[v] == 2){
			res = max(res,can[v]);
			continue;
		}
		else if(vis[v] == 1){
			if(found != -1)
				res = max(res,no[found] & (found >= tim[v]) ? 1 : 0);
			continue;
		}else{
			res = max(res,DFS(v,found));
		}
	}
	no[tim[u]] = 0;
	vis[u] = 2;
	can[u] |= res;
	return res;
}
std::vector<int> who_wins(std::vector<int> a, std::vector<int> r, std::vector<int> u, std::vector<int> v) {

	std::vector<int> res;
	n = a.size();
	for(int i = 0;i<n;i++){
		is[i] = self[i] = to[i] = 0;
	}
	for(int i = 0;i<u.size();i++){
		g[u[i]].push_back(v[i]);
		if(u[i] == v[i])
			self[u[i]] = 1;
		if(u[i] + 1 == v[i])
			to[u[i]] = 1;
	}
	for(int i = 0;i<n;i++)
		is[i] = r[i];
	for(int i = 0;i<n;i++){
		own[i] = a[i];
		if(a[i] != 1)
			flag1 = 0;
		if(a[i] != 0)
			flag2 = 0;
	}
	if(n <= 15){
		int cnt = 0;
		for(int i = 0;i<n;i++){
			for(int j = 0;j<n;j++){
				vis[j] = 0;
			}
			cnt++;
			res.push_back(dfs(i));
		}
	}else if(flag1 == 1){
		for(int i = 0;i<n;++i){
			if(can[i])
				res.push_back(1);
			else{
				for(int j = 0;j<n;j++){
					tim[j] = -1;
					vis[j] = 0;
				}
				cnt = 0;
				res.push_back(DFS(i,-1));
			}
		}
	}else{
		if(is[n-1] && self[n-1])
			res.push_back(1);
		else
			res.push_back(0);
		for(int i = n-2;i>=0;i--){
			if(own[i] == 0){
				int ret = 1;
				ret = min(ret,((!is[i] && self[i]) ? 0 : 1));
				ret = min(ret,((to[i]) ? res.back() : 1));
				res.push_back(ret);
			}else{
				int ret = 0;
				ret = max(ret,((is[i] && self[i]) ? 1 : 0));
				ret = max(ret,((to[i]) ? res.back() : 0));
				res.push_back(ret);				
			}
		}
		reverse(res.begin(),res.end());
	}
	return res;
}

Compilation message (stderr)

train.cpp: In function 'int dfs(int)':
train.cpp:15:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i = 0;i<g[u].size();i++){
                 ~^~~~~~~~~~~~
train.cpp:34:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i = 0;i<g[u].size();i++){
                 ~^~~~~~~~~~~~
train.cpp: In function 'int DFS(int, int)':
train.cpp:64:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0;i<g[u].size();i++){
                ~^~~~~~~~~~~~
train.cpp: In function 'std::vector<int> who_wins(std::vector<int>, std::vector<int>, std::vector<int>, std::vector<int>)':
train.cpp:90:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i = 0;i<u.size();i++){
                ~^~~~~~~~~

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