Cod sursa(job #170676)

Utilizator cos_minBondane Cosmin cos_min Data 3 aprilie 2008 00:36:00
Problema Arbori indexati binar Scor Ascuns
Compilator cpp Status done
Runda Marime 2.09 kb
#include <stdio.h>
#include <fstream>
using namespace std;

#define in "aib.in"
#define out "aib.out"
#define dim 100001

inline int Minim(int a, int b) {
       if ( a < b ) return a;
       return b;
}

int N, M, T;
int Arb[dim];
int C, S;

void Update(int,int);
int Query(int);
int Search(int);

int main()
{
    memset(Arb,0,sizeof(Arb));
    int K, X, Y;
    
    freopen(in,"r",stdin);
    freopen(out,"w",stdout);
    
    scanf("%d%d", &N, &M);
    for ( int i = 1; i <= N; i++ )
    {
        scanf("%d", &T);
        Update(i,T);
    }
    
    for ( ; M; M-- )
    {
        scanf("%d", &K);
        
        if ( K < 2 )
        {
             scanf("%d%d", &X, &Y);
             if ( !K ) Update(X,Y);
             else      printf("%d\n", Query(Y)-Query(X-1));
        }
        else
        {
            scanf("%d", &X);
            
            printf("%d\n", Search(X));
        }
    }
}

int Search(int Sum)
{
    int pos = N+1, B;
    int limst=0, limdr=N+1;
            
    B = N;
    S = Query(B);
            
    if ( S == Sum ) pos = N;
            
    while ( B )
    {
          B = (limst+limdr)>>1;
          S = Query(B);
                  
          if ( S > Sum )
          {
               if ( limdr > B ) limdr = B;
               B -= 1;
          }
          else if ( S == Sum ) pos = Minim(pos,B), limdr = B, B -= 1;
          else
          {
              if ( limst < B ) limst = B;
              B += 1;
          }
                  
          if ( B <= limst ) break;
          if ( B >= limdr ) break;
    }
            
    if ( pos == N+1 ) return -1;
    return pos;
}

void Update(int poz, int val)
{
     C = 0;
     while ( poz <= N )
     {
           Arb[poz] += val;
           while ( !(poz & (1<<C)) ) C++;
           poz += (1<<C);
           C += 1;
     }
}

int Query(int poz)
{
    C = 0, S = 0;
    while ( poz > 0 )
    {
          S += Arb[poz];
          while ( !(poz & (1<<C)) ) C++;
          poz -= (1<<C);
          C += 1;
    }
    
    return S;
}