Segment_tree_min_query

#include <bits/stdc++.h>
#define INF 1000000005
using namespace std;

int ar[1000];
unordered_map <int,int> st; // <index, value>

int query(int seg_ind, int ar_beg, int ar_end, int q_beg, int q_end) {
    if(q_beg >= ar_beg && q_end <= ar_end) {
        return st[seg_ind];
    }
    if(q_beg > ar_end || q_end < ar_beg) {
        return INF;
    }
    int mid = (ar_beg + ar_end) / 2;
    int l = query(2 * seg_ind, ar_beg, mid, q_beg, q_end);
    int r = query(2 * seg_ind+1, mid+1, ar_end, q_beg, q_end);

    return min(l,r);
}

void build_tree(int seg_ind, int ar_beg, int ar_end) {
    if(ar_beg == ar_end) {
        st[seg_ind] = ar[ar_beg];
    }
    int mid = (ar_beg + ar_end) / 2;
    build_tree(2 * seg_ind, ar_beg, mid);
    build_tree(2 * seg_ind+1, mid+1, ar_end);

    st[seg_ind] = min(st[2 * seg_ind], st[2 * seg_ind + 1]);
}

int main() {
    int n;
    cin >> n;
    for(int i=1 ; i<=n ; i++)
        cin >> ar[i];
    //for(int i=1 ; i<=n ; i++) cout << ar[i] << " ";
    build_tree(1,1,n);
    for(auto it: st) cout << (it).first << " -> " << (it).second << endl;
    cout << query(1,1,n,1,n);
}