The Da Vinci Code

#include <bits/stdc++.h>

using namespace std;

#define cin(vec) for(auto& i : vec) cin >> i
#define cin_2d(vec, n, m) for(int i = 0; i < n; i++) for(int j = 0; j < m && cin >> vec[i][j]; j++);
#define cout(vec) for(auto& i : vec) cout << i << " "; cout << "\n";
#define cout_2d(vec, n, m) for(int i = 0; i < n; i++, cout << "\n") for(int j = 0; j < m && cout << vec[i][j] << " "; j++);
#define cout_map(mp) for(auto& [f, s] : mp) cout << f << "  " << s << "\n";
#define Time cerr << "Time Taken: " << (float)clock() / CLOCKS_PER_SEC << " Secs" << "\n";
#define fixed(n) fixed << setprecision(n)
#define ceil(n, m) (((n) / (m)) + ((n) % (m) ? 1 : 0))
#define fill(vec, value) memset(vec, value, sizeof(vec));
#define Num_of_Digits(n) ((int)log10(n)+1)
#define all(vec) vec.begin(),vec.end()
#define rall(vec) vec.rbegin(),vec.rend()
#define sz(x) int(x.size())
#define TC int t; cin >> t;   while(t--)
#define fi first
#define se second
#define Pair pair < int, int >
#define ll long long
#define ull unsigned long long
#define Mod  1'000'000'007
#define OO 2'000'000'000
#define EPS 1e-9
#define PI acos(-1)
#define imin INT_MIN
#define imax INT_MAX
#define getline(s) getline(cin >> ws , s)
#define pb(x) push_back(x)
#define to_decimal(bin) stoi(bin, nullptr, 2)

void AbdEl3al(){
    ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout);
#endif
    Time
}

vector < ll > prefix_sum;

void prefix(vector < ll >& nums){
    prefix_sum.resize(sz(nums) + 1);
    for(int i = 1; i <= sz(nums); i++){
        prefix_sum[i] = prefix_sum[i - 1] + nums[i - 1];
    }
}

ll Max_Size(vector < ll >& nums, int size){
    ll mx = imin;
    for(int i = 0; i <= sz(nums) - size; i++){
        mx = max(mx, prefix_sum[i + size] - prefix_sum[i]);
    }
    return mx;
}

int Binary_Search(vector < ll >& nums, ll x){
    ll l = 1, r = sz(nums), ans = -1;
    while(l <= r){
        ll m = l + (r - l) / 2;
        (Max_Size(nums, m) <= x ? l = m + 1, ans = m : r = m - 1);
    }
    return ans;
}


int main (){
    AbdEl3al();
    ll n, x;
    cin >> n >> x;
    vector < ll > nums(n);
    for(auto& i : nums) cin >> i;
    prefix(nums);
    cout << Binary_Search(nums, x);
    return 0;
}