Lucky prefixes

input/code.cpp: In function 'int main()':
input/code.cpp:57:10: warning: unused variable 'a' [-Wunused-variable]
   57 |     auto a = st.query(2,3);
      |          ^

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

template<class T, class Op>
struct SegTree {
    int n;
    T ID;
    Op op;
    vector<T> st;
    SegTree(int n=0, T ID=T(), Op op=Op()) {init(n, ID, op); }
    void init(int n_, T ID_, Op op_=Op()) {
        n = n_;  ID = ID_; op= op_;
        st.assign(2*n, ID);
    }
    void build(const vector<T> &a) {
        n = (int)a.size();
        st.assign(2*n, ID);
        for (int i = 0; i < n; i++) st[n+i] = a[i];
        for(int i = n-1; i > 0; i--) st[i] = op(st[i<<1], st[i<<1|1]);
    }
    void set(int i, T v) {
        for(st[i += n] = v; i > 1; i >>= 1)
            st[i>>1] = op(st[i], st[i^1]);
    }
    T query(int l , int r) const {
        T resL = ID, resR = ID;
        for(l += n, r += n+1; l <r; l >>= 1, r >>= 1) {
            if (l & 1) resL = op(resL, st[l++]);
            if (r & 1) resR = op(st[--r], resR);
        }
        return op(resL, resR);
    }
};


const long long ID = 0;

struct Op {
    long long operator() (long long a, long long b ) const {
        return a + b;
    }
};


int main () {
    //freopen("linput.txt", "r", stdin);
    int n, q;
    cin >> n >> q;

    auto st = SegTree(n, ID, Op());

    for(int i =0; i <n; i++) {
        long long d; cin >> d;
        st.set(i, d);
    }

    auto a = st.query(2,3);

    while(q--) {
        int i, j, k;
        cin >> i >> j >> k;
        if(i == 1) {
            st.set(--j, k);
        }
        else {
            --j; --k;
            bool ok = true;
            for (int p = j; p <=k; p++) {
                if (st.query(j, p) < 0) {
                    cout << "NO\n";
                    ok = false;
                    break;
                }
            }
            if (ok) cout << "YES\n";
        }
    }
    

    return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: TIME LIMIT EXCEEDED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED