Cod sursa(job #1723619)

Utilizator gabrielinelusGabriel-Robert Inelus gabrielinelus Data 1 iulie 2016 02:06:19
Problema Arbori de intervale Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 2.4 kb
#include <cstdio>
#include <algorithm>

std::vector<int> val;


#define DIM 666013

char buffer[DIM];
int poz = DIM - 1;

void read(int &A)
{
    A = 0;
    while('0' > buffer[poz] || buffer[poz] > '9')
        if(++poz == DIM) fread(buffer,1,DIM,stdin),poz = 0;
    while('0' <= buffer[poz] && buffer[poz] <= '9')
    {
        A = A * 10 + buffer[poz] - 48;
        if(++poz == DIM) fread(buffer,1,DIM,stdin),poz = 0;
    }
}

class SegmentTree{
private:
    std::vector<int> aint;
public:
    SegmentTree(){}
    SegmentTree(int k){
        aint.resize(4 * k);
    }
    void resizeSTree(int k){
        aint.resize(4 * k);
    }
    void query(int li,int lf,int pz,int &A,int &B, int &answer)
    {
        if(A <= li && lf <= B){
            answer = std::max(answer,aint[pz]);
            return;
        }
        int m = li + ((lf - li) >> 1);
        if(A <= m) query(li, m, pz << 1, A, B, answer);
        if(m < B) query(m + 1, lf, (pz << 1) | 1, A, B, answer);
    }
    void update(int li,int lf, int pz, int &pos, int &_newX)
    {
        if(li == lf){
            aint[pz] = _newX;
            return;
        }
        int m = li + ((lf - li) >> 1);
        if(pos <= m)    update(li, m, pz << 1, pos, _newX);
        else            update(m + 1, lf, (pz << 1) | 1, pos, _newX);
        aint[pz] = std::max(aint[pz << 1], aint[(pz << 1) | 1]);
    }
    void build(int li,int lf,int pz)
    {
        if(li == lf){
            aint[pz] = val[li];
            return;
        }
        int m = li + ((lf - li) >> 1);
        build(li, m, pz << 1);
        build(m + 1, lf, (pz << 1) | 1);
        aint[pz] = std::max(aint[pz << 1], aint[(pz << 1) | 1]);
    }
};
SegmentTree STree;
int N,M;

void read()
{
    read(N);read(M);
    val.resize(N + 1);
    STree.resizeSTree(N);
    for(int i = 1; i <= N; ++i)
        read(val[i]);
    STree.build(1,N,1);
}

void solve()
{
    const int INF = 0x3f3f3f3f;
    int op,a,b,answer;
    for(int i = 1; i <= M; ++i)
    {
        read(op);read(a);read(b);
        if(op == 0){
            answer = -INF;
            STree.query(1,N,1,a,b,answer);
            printf("%d\n",answer);
            continue;
        }
        STree.update(1,N,1,a,b);
    }
}

int main()
{
    freopen("arbint.in","r",stdin);
    freopen("arbint.out","w",stdout);

    read();
    solve();

    return 0;
}