Submission #508399

#	Time	Username	Problem	Language	Result	Execution time	Memory
508399		alextodoran	Safety (NOI18_safety)	C++17	100 / 100	260 ms	22620 KiB

safety

/**
 ____ ____ ____ ____ ____
||a |||t |||o |||d |||o ||
||__|||__|||__|||__|||__||
|/__\|/__\|/__\|/__\|/__\|

**/

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

const int N_MAX = 200000;

int N;
ll H;

ll S[N_MAX + 2];

ll valueAtZero;

int deletedLeft;
multiset <ll> leftPivots;
multiset <ll> rightPivots;

ll shiftLeft, shiftRight;

void addPivot (ll piv) {
    if (rightPivots.empty() == true
    || *rightPivots.begin() + shiftRight <= piv) {
        rightPivots.insert(piv - shiftRight);
    } else {
        leftPivots.insert(piv - shiftLeft);
    }
    if ((int) leftPivots.size() + deletedLeft > (int) rightPivots.size()) {
        rightPivots.insert(*prev(leftPivots.end()) + shiftLeft - shiftRight);
        leftPivots.erase(prev(leftPivots.end()));
    }
    if ((int) rightPivots.size() > (int) leftPivots.size() + deletedLeft + 1) {
        leftPivots.insert(*rightPivots.begin() + shiftRight - shiftLeft);
        rightPivots.erase(rightPivots.begin());
    }
}

void expand () {
    shiftLeft -= H;
    shiftRight += H;
    while (leftPivots.empty() == false && *leftPivots.begin() < 0) {
        leftPivots.erase(leftPivots.begin());
        deletedLeft++;
    }
    valueAtZero -= H * (int) leftPivots.size();
}

ll getMin () {
    ll value = valueAtZero;
    for (ll piv : leftPivots) {
           value -= (piv + shiftLeft);
    }
    return value;
}

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

    cin >> N >> H;
    for (int i = 1; i <= N; i++) {
        cin >> S[i];
    }

    valueAtZero += S[1];
    addPivot(S[1]);
    addPivot(S[1]);

    for (int i = 2; i <= N; i++) {
        valueAtZero += S[i];
        expand();
        addPivot(S[i]);
        addPivot(S[i]);
    }

    cout << getMin() << "\n";

    return 0;
}

• Subtask 1: 3 / 3
• Subtask 2: 4 / 4
• Subtask 3: 9 / 9
• Subtask 4: 5 / 5
• Subtask 5: 6 / 6
• Subtask 6: 11 / 11
• Subtask 7: 11 / 11
• Subtask 8: 22 / 22
• Subtask 9: 29 / 29