Submission #123076

#	Time	Username	Problem	Language	Result	Execution time	Memory
123076		nxteru	Tropical Garden (IOI11_garden)	C++14	0 / 100	12 ms	11068 KiB

garden

#include "garden.h"
#include "gardenlib.h"
#include <bits/stdc++.h>
using namespace std;
typedef pair<int,int> P;
#define F first
#define S second
#define PB push_back
int n,m,q,k,nx[300005],t[2],fi[150005],vis[300005],sz[300005],d[2][300005];
vector<P>e[150005];
vector<int>g[300005];
bool rp[300005];
void dfs(int v,int cn){
	vis[v]=k;
	sz[v]=cn;
	int u=nx[v];
	if(vis[u]==-1)dfs(u,cn+1);
	else if(vis[u]==k){
		int s=sz[u]+1-cn;
		u=v;
		do{
			u=nx[u];
			rp[u]=true;
			sz[u]=s;
		}while(u!=v);
	}
}
void count_routes(int N, int M, int p, int R[][2], int Q, int G[]){
	n=N,m=M,q=Q;
	for(int i=0;i<m;i++){
		int a=R[i][0],b=R[i][1];
		e[a].PB(P(i,0));
		e[b].PB(P(i,1));
	}
	for(int i=0;i<m;i++){
		int a=R[i][0],b=R[i][1];
		if(e[b].size()==1||e[b][0].F!=i)nx[i*2]=e[b][0].F*2+e[b][0].S;
		else nx[i*2]=e[b][1].F*2+e[b][1].S;
		if(e[a].size()==1||e[a][0].F!=i)nx[i*2+1]=e[a][0].F*2+e[a][0].S;
		else nx[i*2+1]=e[a][1].F*2+e[a][1].S;
	}
	for(int i=0;i<n;i++)fi[i]=e[i][0].F*2+e[i][0].S;
	t[0]=fi[p];
	if(e[p].size()>1)t[1]=e[p][1].F*2+e[p][1].S;
	else t[1]=t[0];
	for(int i=0;i<m*2;i++)vis[i]=-1;
	for(int i=0;i<m*2;i++){
		if(vis[i]==-1){
			dfs(i,0);
			k++;
		}
	}
	for(int i=0;i<m*2;i++)g[nx[i]].PB(i);
	for(int i=0;i<2;i++){
		for(int j=0;j<m*2;j++)d[i][j]=-1;
		d[i][t[i]]=0;
		queue<int>bfs;
		bfs.push(t[i]);
		while(!bfs.empty()){
			int v=bfs.front(),c=d[i][v];
			bfs.pop();
			for(int j=0;j<g[v].size();j++){
				int u=g[v][j];
				if(d[i][u]==-1){
					d[i][u]=c+1;
					bfs.push(u);
				}
			}
		}
	}
	for(int i=0;i<q;i++){
		int ans=0,x=G[i];
		for(int j=0;j<n;j++){
			int v=fi[j];
			bool ok=false;
			for(int l=0;l<2;l++){
				if(d[l][v]==x||(rp[t[l]]&&d[l][v]<=x&&(x-d[l][v])%sz[t[l]]==0))ok=true;
			}
			if(ok)ans++;
		}
		answer(ans);
	}
}

Compilation message (stderr)

garden.cpp: In function 'void count_routes(int, int, int, int (*)[2], int, int*)':
garden.cpp:62:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for(int j=0;j<g[v].size();j++){
                ~^~~~~~~~~~~~

• Subtask 1: 0 / 49
• Subtask 2: 0 / 20
• Subtask 3: 0 / 31