Dynamic Range Minimum Queries

#include <bits/stdc++.h> 
using namespace std;
#define REP(i,a,b) for (int i = a; i < b; i++)


int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    int n;
    int q;
    cin>>n>>q;
    vector<int> x(n);
    vector<int> tree(2*n);
    REP(i,0,n){
        int a;
        cin>>a;
        x[i]=a;
        tree[n+i]=a;
    }
    REP(i,0,n){
        for (i /= 2; i >= 1; i /= 2) {
            tree[i] = min(tree[2*i],tree[2*i+1]);
        }
    }
    REP(i,0,q){
        int quer;
        cin>>quer;
        if (quer==1){
            int k;
            int u;
            cin>>k>>u;
            tree[k] = u;
            for (k /= 2; k >= 1; k /= 2) {
                tree[k] = min(tree[2*k],tree[2*k+1]);
            }
        }
        else{
            int a;
            int b;
            cin>>a>>b;
            a += n; b += n;
            int m = 0;
            while (a <= b) {
                if (a%2 == 1) m = min(m,tree[a++]);
                if (b%2 == 0) m = min(m,tree[b--]);
                a /= 2; b /= 2;
            }
        }


    }
}

Test 1

Verdict: WRONG ANSWER

Test 2

Verdict: WRONG ANSWER