Cod sursa(job #1989539)

Utilizator Horia14Horia Banciu Horia14 Data 7 iunie 2017 21:24:02
Problema Arbori de intervale Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.55 kb
#include<cstdio>
#define MAX_N 100000
#define MIN_VALUE -0x7fffffff
using namespace std;

int segTree[4*(MAX_N+1)], v[MAX_N+1], n, m, a, b;

inline int maxim(int x, int y)
{
    if(x > y) return x;
    return y;
}

void BuildTree(int low, int high, int pos)
{
    if(low == high)
    {
        segTree[pos] = v[low];
        return;
    }
    int mid = (low + high) >> 1;
    BuildTree(low,mid,2*pos);
    BuildTree(mid+1,high,2*pos+1);
    segTree[pos] = maxim(segTree[2*pos],segTree[2*pos+1]);
}

void UpdateSegTree(int low, int high, int pos)
{
    if(low == high)
    {
        segTree[pos] = b;
        return;
    }
    int mid = (low + high) >> 1;
    if(a <= mid) UpdateSegTree(low,mid,2*pos);
    else UpdateSegTree(mid+1,high,2*pos+1);
    segTree[pos] = maxim(segTree[2*pos],segTree[2*pos+1]);
}

int Query(int low, int high, int pos)
{
    if(a <= low && high <= b)
        return segTree[pos];
    if(a > high || b < low)
        return MIN_VALUE;
    int mid = (low + high) >> 1;
    return maxim(Query(low,mid,2*pos),Query(mid+1,high,2*pos+1));
}

int main()
{
    int i, op;
    FILE *fin, *fout;
    fin = fopen("arbint.in","r");
    fout = fopen("arbint.out","w");
    fscanf(fin,"%d%d",&n,&m);
    for(i=1; i<=n; i++)
        fscanf(fin,"%d",&v[i]);
    BuildTree(1,n,1);
    for(i=1; i<=m; i++)
    {
        fscanf(fin,"%d%d%d",&op,&a,&b);
        if(op == 0)
            fprintf(fout,"%d\n",Query(1,n,1));
        else UpdateSegTree(1,n,1);
    }
    fclose(fin);
    fclose(fout);
    return 0;
}