segmentTreeConstruct

#include <iostream>
#include <algorithm>
#include <climits>
using namespace std;

int inf = INT_MAX;

int segment[100]={0};

void constructTree(int number[],int start, int end, int pos){

    segment[pos]=0;

    if(start == end){

        segment[pos] = number[start];
        return;
    }

    int mid = (start+end) / 2;

    constructTree(number, start, mid, pos*2);
    constructTree(number, mid+1, end, pos*2+1);

    segment[pos] = min(segment[pos*2],segment[pos*2+1]);



    }


int query(int start, int end, int qstart, int qend, int pos){


        if(start >= qstart && end<=qend)
            return segment[pos];


        if(start > qend || end<qstart)
            return inf;

    int mid = (start + end) /2;
    int x = query(start,mid, qstart, qend, pos*2);
    int y = query(mid+1, end, qstart, qend, pos*2+1);

    return min(x,y);

}


int main(int argc, char **argv)
{


    /*                 0  1   2    3   3 5 6  7  */
    int number[8] = {-11,-1,-100,-400,-2,6,7,-1111};

    int size = sizeof(number)/sizeof(number[0])-1;


    constructTree(number,0,size, 1);


    //for(int  i=0; i<20; i++)

        //cout<<i<<":"<<segment[i]<<" \n";


    cout<<query(0, size, 0, 7,1)<<"\n";
    cout<<query(0, size, 0, 3,1)<<"\n";
    cout<<query(0, size, 4, 7,1)<<"\n";
    cout<<query(0, size, 1, 3,1)<<"\n";





    return 0;
}