#include <bits/stdc++.h>
#define boAshraf ios_base::sync_with_stdio(false); cin.tie(NULL);
#define ll long long
#define sz(s) (int)(s).size()
#define all(s) (s).begin(),(s).end()
using namespace std;
void File();
void sol();
class WaveletTree {
public:
    int low, high;
    WaveletTree *left, *right;
    vector<int> freq;

    // Constructor to build the Wavelet Tree
    WaveletTree(vector<int>& arr, int l, int r, int lo, int hi) : low(lo), high(hi), left(nullptr), right(nullptr) {
        if (lo == hi || l > r) return;

        int mid = (lo + hi) / 2;
        freq.reserve(r - l + 2);
        freq.push_back(0);

        for (int i = l; i <= r; i++) {
            freq.push_back(freq.back() + (arr[i] <= mid));
        }

        vector<int> leftArr, rightArr;
        for (int i = l; i <= r; i++) {
            if (arr[i] <= mid)
                leftArr.push_back(arr[i]);
            else
                rightArr.push_back(arr[i]);
        }

        if (!leftArr.empty()) {
            left = new WaveletTree(leftArr, 0, sz(leftArr) - 1, lo, mid);
        }
        if (!rightArr.empty()) {
            right = new WaveletTree(rightArr, 0, sz(rightArr) - 1, mid + 1, hi);
        }
    }

    // Get answer for the query
    int get_ans(int l, int r, int k) {
        if (r - l + 1 < k) return 1e9;
        if (low == high) return low;

        int leftCount = freq[r + 1] - freq[l];
        int ans = 1e9;

        if (left && leftCount >= k) {
            ans = min(ans, left->get_ans(freq[l], freq[r + 1] - 1, k));
        }
        if (right && r - l + 1 - leftCount >= k) {
            ans = min(ans, right->get_ans(l - freq[l], r - freq[r + 1], k));
        }

        return ans;
    }

    ~WaveletTree() {
        delete left;
        delete right;
    }
};
int main() {
    boAshraf
    File();
    int t = 1;
//    cin >> t;
    while (t--) {
        sol();
    }
    return 0;
}

void sol() {
    int n,q;
    cin>>n>>q;
    vector<int>v(n);
    for(auto &it:v)cin>>it;
    vector<int>uni=v;
    sort(all(uni));
    uni.erase(unique(all(uni)),uni.end());
    vector<int>id=v;
    for(auto &it:id){
        it=lower_bound(all(uni),it)-uni.begin();
    }
    WaveletTree wlt(id,0,n-1,0,sz(uni)-1);
    int l,r,k,ans;
    while(q--){
        cin>>l>>r>>k;
        l--,r--;
        ans=wlt.get_ans(l,r,(r-l+1)/k+1);
        if(ans==1e9)ans=-1;
        else ans=uni[ans];
        cout<<ans<<'\n';
    }
}

void File() {
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
}