Submission #1154259

#	Time	Username	Problem	Language	Result	Execution time	Memory
1154259		simuyu	Po (COCI21_po)	C++20	70 / 70	6 ms	1604 KiB

Main

#include <bits/stdc++.h>
using namespace std;
#define f first
#define s second
#define ll long long

ll N;
ll diffs[100005];

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    cin >> N;
    ll prev = 0, t;
    for (ll i=0; i<N; i++) {
        cin >> t;
        diffs[i] = t-prev;
        prev=t;
    }
    diffs[N] = 0 - prev;

    // use stack
    ll res = 0;
    stack<ll> nums; // number of positives stored
    for (ll i=0; i<=N; i++) {
        if (diffs[i] == 0) continue;
        if (diffs[i] > 0) {
            // positive - add to stack
            nums.push(diffs[i]);
        } else {
            // negative - remove from stack
            ll num_rem = -diffs[i]; // amount that we need to remove from stack
            while (true) {
                if (nums.top() > num_rem) {
                    // we remove a bit from nums.top()
                    res ++;
                    ll t = nums.top() - num_rem;
                    nums.pop(); nums.push(t);
                    break;
                } else {
                    // remove nums.top()
                    res ++;
                    num_rem -= nums.top();
                    nums.pop();
                    if (num_rem == 0) break;
                }
            }
        }
    }

    if (!nums.empty()) { // should never happen. TLE if it happens
        ll t=0;
        while (true) t++;
    }

    cout << res << endl;


    return 0;
}

• Subtask 1: 70 / 70