Submission #465524

#	Time	Username	Problem	Language	Result	Execution time	Memory
465524		alextodoran	Street Lamps (APIO19_street_lamps)	C++17	20 / 100	5071 ms	524292 KiB

street_lamps

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

**/

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

const int N_MAX = 300000;
const int Q_MAX = 300000;

int n, q;

bool light[N_MAX + 2];

struct SGTNode
{
    int len;
    int pref;
    int suff;
};

SGTNode join (const SGTNode &u, const SGTNode &v)
{
    return SGTNode
    {
        u.len + v.len,
        (u.pref == u.len ? u.len + v.pref : u.pref),
        (v.suff == v.len ? v.len + u.suff : v.suff)
    };
}

SGTNode SGT[N_MAX * 4 + 2];

void build (int node, int l, int r)
{
    if(l == r)
    {
        SGT[node] = SGTNode{1, light[l], light[l]};
        return;
    }

    int mid = (l + r) / 2;
    int lSon = node * 2, rSon = node * 2 + 1;

    build(lSon, l, mid);
    build(rSon, mid + 1, r);

    SGT[node] = join(SGT[lSon], SGT[rSon]);
}
void build ()
{
    build(1, 1, n);
}

void update (int node, int l, int r, int upos)
{
    if(l == r)
    {
        SGT[node].pref = 1 - SGT[node].pref;
        SGT[node].suff = 1 - SGT[node].suff;
        return;
    }

    int mid = (l + r) / 2;
    int lSon = node * 2, rSon = node * 2 + 1;

    if(upos <= mid)
        update(lSon, l, mid, upos);
    else
        update(rSon, mid + 1, r, upos);

    SGT[node] = join(SGT[lSon], SGT[rSon]);
}
void update (int upos)
{
    update(1, 1, n, upos);
}

SGTNode query (int node, int l, int r, int ql, int qr)
{
    if(ql <= l && r <= qr)
        return SGT[node];

    int mid = (l + r) / 2;
    int lSon = node * 2, rSon = node * 2 + 1;

    if(ql <= mid && mid + 1 <= qr)
        return join(query(lSon, l, mid, ql, qr), query(rSon, mid + 1, r, ql, qr));
    else if(ql <= mid)
        return query(lSon, l, mid, ql, qr);
    else
        return query(rSon, mid + 1, r, ql, qr);
}
SGTNode query (int ql, int qr)
{
    if(ql > qr)
        return SGTNode{0, 0, 0};
    return query(1, 1, n, ql, qr);
}

unordered_map <int, int> BIT[(N_MAX + 1) + 2];

void BITupdate (int x, int y, int uval)
{
    for(int i = x; i <= n + 1; i += i & -i)
        for(int j = y; j <= n + 1; j += j & -j)
            BIT[i][j] += uval;
}
void BITupdate (int lx, int rx, int ly, int ry, int uval)
{
    if(lx > rx || ly > ry)
        return;
    BITupdate(lx, ly, uval);
    BITupdate(rx + 1, ly, -uval);
    BITupdate(lx, ry + 1, -uval);
    BITupdate(rx + 1, ry + 1, uval);
}

int BITquery (int x, int y)
{
    int answer = 0;
    for(int i = x; i >= 1; i -= i & -i)
        for(int j = y; j >= 1; j -= j & -j)
            answer += BIT[i][j];
    return answer;
}

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

    cin >> n >> q;

    {
        string s;
        cin >> s;

        for(int i = 1; i <= n; i++)
            light[i] = (s[i - 1] == '1');
    }

    build();

    for(int i = 2; i <= n + 1; i++)
        if(light[i - 1] == true)
        {
            int lLen = query(1, i - 1).suff;
            BITupdate(i - lLen, i - 1, i, i, + q);
        }

    for(int qi = 1; qi <= q; qi++)
    {
        string type;
        cin >> type;

        if(type == "toggle")
        {
            int upos;
            cin >> upos;

            int lLen = query(1, upos - 1).suff;
            int rLen = query(upos + 1, n).pref;

            if(light[upos] == true)
                BITupdate(upos - lLen, upos, upos + 1, upos + 1 + rLen, - (q - qi));

            light[upos] = !light[upos];
            update(upos);

            if(light[upos] == true)
                BITupdate(upos - lLen, upos, upos + 1, upos + 1 + rLen, + (q - qi));
        }
        else
        {
            int l, r;
            cin >> l >> r;

            int answer = BITquery(l, r);
            if(query(l, r - 1).pref == r - l)
                answer -= (q - qi);

            cout << answer << "\n";
        }
    }

    return 0;
}

• Subtask 1: 20 / 20
• Subtask 2: 0 / 20
• Subtask 3: 0 / 20
• Subtask 4: 0 / 20
• Subtask 5: 0 / 20