Cod sursa(job #140674)

Utilizator pitbullpitbulll pitbull Data 22 februarie 2008 09:24:56
Problema Stramosi Scor 40
Compilator c Status done
Runda Arhiva de probleme Marime 1.19 kb
# include <stdio.h>
# include <math.h>
# define IN "stramosi.in"
# define OUT "stramosi.out"
# define MAXLINE 20
# define MAXCOL 250001 
int N,M;

void gaseste(FILE*,int,int);
void solve();
int mat[MAXLINE][MAXCOL];
int parinte(int,int);

int main(){
	solve();
	return 0;
}

void solve(){
	FILE *in=fopen(IN,"rt");
	FILE *out=fopen(OUT,"wt");
	fscanf(in,"%d %d",&N,&M);
	register int i,j;
	for (i=0;i<log(N);i++)	
		for (j=1;j<=N;j++)
			mat[i][j]=-1;
	int P,Q;
	for (i=1;i<=N;i++)
		fscanf(in,"%d",&mat[0][i]);
	for (i=0;i<M;i++){
		fscanf(in,"%d %d",&Q,&P);
		gaseste(out,P,Q);
	}
	fclose(out);		
	fclose(in);
}

void gaseste(FILE* out,int P,int Q){
	//omul are id-ul Q
	//vreau al P-lea parinte
	int i;
	//putem avea maxim 2^18 parinti,aproximez la 2^20
	int p=Q;
	for (i=20;i>=0;i--)
		if(P & (1 << i ) ){
			p=parinte(p,i);//afla cel de-al 2^i-lea parinte al lui p
		}
	fprintf(out,"%d\n",p);	
}

int parinte(int p,int i){
	//afla cel de-al 2^i-lea parinte al lui p
	//cu alte cuvinte afla care este valoarea lui mat[i][p]		
	if(i==0||mat[i][p]!=-1)
		return mat[i][p];
	else {
		mat[i][p]=parinte(parinte(p,i-1),i-1);
		return mat[i][p];	
	}
	return 0;
}