Produto do intervalo - Neps

#include <bits/stdc++.h>

#define forn(l, r) for(int i = l; i < (r); ++i)
#define forj(l, r) for(int j = l; j < (r); ++j)
#define TAM 1000100
#define SYNC ios::sync_with_stdio(0);
#define $ << ' ' <<
#define F first
#define S second
#define endl '\n'


using namespace std;

using ll = long long int;
using ii = pair<int, int>;
using vii = vector<ii>;
using vi = vector<int>;
using graph = vector<vi>;
const int INF = 0x3f3f3f3f;
const int MAXN = 112345;
const ll mod = 1000000007;

ll seq[MAXN], segt[4*MAXN+1], n;

void build (int node, int l, int r) {
    if (l == r) {
        segt[node] = seq[l];
    }else {
        build(2*node+1, l, (l+r)/2);
        build(2*node+2, (l+r)/2+1, r);
        segt[node] = segt[node*2+1] * segt[node*2+2];
    }

}

void update (int node, int l, int r, int pos, int val) {
    if (l == r) {
        seq[pos] = segt[node] = val;
    } else {
        int mid = (l+r)/2;
        if (pos <= mid) update(2*node+1, l, mid, pos, val);
        else update(2*node+2, mid+1, r, pos, val);
        segt[node] = segt[node*2+1] * segt[node*2+2];
    }
}

int query  (int node, int l, int r, int low, int up) {
    if (low > r || up < l) {
        return 1;
    }
    if (low <= l && up >= r) {
        return segt[node];
    }
    int mid = (l+r)/2;
    return query(node*2+1, l, mid, low, up)*query(node*2+2, mid+1, r, low, up);
}


int main()
{
    SYNC
    int k;
        while(cin >> n >> k){
        for (int i = 0; i < n; ++i) {
            cin >> seq[i];
            if (seq[i] > 0) {
                seq[i] = 1;
            } else if (seq[i] < 0) {
                seq[i] = -1;
            }
        }
        build(0, 0, n-1);
        vector<char> ans;
        char op;
        int a, b;
        while (k--) {
            cin >> op >> a >> b;
            if (op == 'C') {
                if (b > 0) {
                    b = 1;
                } else if (b < 0) {
                    b = -1;
                }
                update(0, 0, n-1, a-1, b);
            } else {
                a = query(0, 0, n-1, a-1, b-1);
                if (a > 0) {
                    ans.push_back('+');
                } else if (a == 0) {
                    ans.push_back('0');
                } else {
                    ans.push_back('-');
                }
            }
        }
        for (int i = 0; i < (int) ans.size(); ++i) {
            cout << ans[i];
        }
        cout << endl;
    }


    return 0;
}