Submission #951277

#	Time	Username	Problem	Language	Result	Execution time	Memory
951277		Nhoksocqt1	Rainforest Jumps (APIO21_jumps)	C++17	27 / 100	914 ms	244148 KiB

jumps

#include<bits/stdc++.h>
using namespace std;

#define inf 0x3f3f3f3f
#define sz(x) int((x).size())
#define fi first
#define se second
typedef long long ll;
typedef pair<int, int> ii;

template<class X, class Y>
	inline bool maximize(X &x, const Y &y) {return (x < y ? x = y, 1 : 0);}
template<class X, class Y>
	inline bool minimize(X &x, const Y &y) {return (x > y ? x = y, 1 : 0);}

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int Random(int l, int r) {
    return uniform_int_distribution<int>(l, r)(rng);
}

const int MAXN = 200005;

struct SegNode {
    int cnt, id, L, R;
} seg[50 * MAXN];

int P[MAXN][18], Pn[MAXN][18], Pi[MAXN][18], Pa[MAXN][18];
int h[MAXN], dist[MAXN], version[MAXN], nxt[MAXN], prv[MAXN], nTree, nArr;
bool check_sub1;

int update(int oldID, int l, int r, int pos, int cnt, int id) {
    if(l == r) {
        seg[++nTree] = seg[oldID];
        seg[nTree].cnt += cnt;
        seg[nTree].id = id;
        return nTree;
    }

    int cur(++nTree), mid = (l + r) >> 1;
    seg[cur] = seg[oldID];

    if(pos <= mid) {
        seg[cur].L = update(seg[oldID].L, l, mid, pos, cnt, id);
    } else {
        seg[cur].R = update(seg[oldID].R, mid + 1, r, pos, cnt, id);
    }

    seg[cur].cnt = seg[seg[cur].L].cnt + seg[seg[cur].R].cnt;
    return cur;
}

int walkOnSeg(int idr, int idl, int l, int r, int u, int v) {
    if(u <= l && r <= v) {
        while(l < r) {
            int mid = (l + r) >> 1;
            if(seg[seg[idr].R].cnt - seg[seg[idl].R].cnt > 0) {
                idr = seg[idr].R, idl = seg[idl].R;
                l = mid + 1;
            } else {
                idr = seg[idr].L, idl = seg[idl].L;
                r = mid;
            }
        }

        return seg[idr].id;
    }

    int res(-1), mid = (l + r) >> 1;
    if(mid + 1 <= v && seg[seg[idr].R].cnt - seg[seg[idl].R].cnt > 0)
        res = walkOnSeg(seg[idr].R, seg[idl].R, mid + 1, r, u, v);

    if(res < 0 && mid >= u && seg[seg[idr].L].cnt - seg[seg[idl].L].cnt > 0)
        res = walkOnSeg(seg[idr].L, seg[idl].L, l, mid, u, v);

    return res;
}

void init(int _N, vector<int> _H) {
    nArr = _N;

    check_sub1 = 1;
    for (int i = 1; i <= nArr; ++i) {
        h[i] = _H[i - 1];
        check_sub1 &= (i == 1 || h[i] > h[i - 1]);
    }

    stack<int> st;
    for (int i = 1; i <= nArr; ++i) {
        while(sz(st) && h[st.top()] <= h[i])
            st.pop();

        prv[i] = (sz(st)) ? st.top() : 0;
        st.push(i);
    }

    while(sz(st))
        st.pop();

    for (int i = nArr; i > 0; --i) {
        while(sz(st) && h[st.top()] <= h[i])
            st.pop();

        nxt[i] = (sz(st)) ? st.top() : nArr + 1;
        st.push(i);
    }

    nTree = 0;
    for (int i = 1; i <= nArr; ++i)
        version[i] = update(version[i - 1], 1, nArr, h[i], +1, i);

    for (int i = 1; i <= nArr; ++i) {
        Pi[i][0] = Pa[i][0] = h[i];
        P[i][0] = (h[nxt[i]] >= h[prv[i]]) ? nxt[i] : prv[i];
        Pn[i][0] = nxt[i];
    }

    P[0][0] = 0, P[nArr + 1][0] = Pn[nArr + 1][0] = nArr + 1;
    for (int j = 1; (1 << j) <= nArr; ++j) {
        for (int i = 0; i <= nArr + 1; ++i) {
            P[i][j] = P[P[i][j - 1]][j - 1];
            Pn[i][j] = Pn[Pn[i][j - 1]][j - 1];
            if(i + (1 << j) -  1 <= nArr) {
                Pi[i][j] = min(Pi[i][j - 1], Pi[i + (1 << (j - 1))][j - 1]);
                Pa[i][j] = max(Pa[i][j - 1], Pa[i + (1 << (j - 1))][j - 1]);
            }
        }
    }
}

int brute(int a, int b, int c, int d) {
    for (int i = 1; i <= nArr; ++i)
        dist[i] = -1;

    queue<int> qu;
    for (int i = a; i <= b; ++i) {
        qu.push(i);
        dist[i] = 0;
    }

    while(sz(qu)) {
        int u(qu.front()); qu.pop();

        if(u >= c && u <= d)
            return dist[u];

        if(prv[u] > 0 && dist[prv[u]] < 0) {
            dist[prv[u]] = dist[u] + 1;
            qu.push(prv[u]);
        }

        if(nxt[u] <= nArr && dist[nxt[u]] < 0) {
            dist[nxt[u]] = dist[u] + 1;
            qu.push(nxt[u]);
        }
    }

    return -1;
}

inline int getMin(int l, int r) {
    int log = 31 - __builtin_clz(r - l + 1);
    return min(Pi[l][log], Pi[r - (1 << log) + 1][log]);
}

inline int getMax(int l, int r) {
    int log = 31 - __builtin_clz(r - l + 1);
    return max(Pa[l][log], Pa[r - (1 << log) + 1][log]);
}

int sub5(int a, int c) {
    int res(0);
    for (int i = 31 - __builtin_clz(nArr); i >= 0; --i) {
        if(P[a][i] != 0 && P[a][i] != nArr + 1 && h[P[a][i]] < h[c]) {
            res += (1 << i);
            a = P[a][i];
        }
    }

    for (int i = 31 - __builtin_clz(nArr); i >= 0; --i) {
        if(Pn[a][i] != nArr + 1 && h[Pn[a][i]] <= h[c]) {
            res += (1 << i);
            a = Pn[a][i];
        }
    }

    assert(a == c);
    return res;
}

int magicFunc(int a, int b, int c, int d) {
    int maxBetween(-1), maxEnd = getMax(c, d);
    if(b + 1 <= c - 1)
        maxBetween = getMax(b + 1, c - 1);

    assert(maxEnd > 1);
    int u = walkOnSeg(version[b], version[a - 1], 1, nArr, 1, maxEnd - 1);
    assert(u != -1);

    int res(0);
    for (int i = 31 - __builtin_clz(nArr); i >= 0; --i) {
        if(P[u][i] != 0 && P[u][i] != nArr + 1 && h[P[u][i]] < maxBetween) {
            u = P[u][i];
            res += (1 << i);
        }
    }

    if(h[u] < maxBetween) {
        u = nxt[u];
        ++res;
    }

    if(u < c) {
        u = nxt[u];
        ++res;
    }

    assert(c <= u && u <= d);
    return res;
}

int minimum_jumps(int a, int b, int c, int d) {
    ++a, ++b, ++c, ++d;
    if(check_sub1)
        return c - b;

    int minStart = getMin(a, b), maxBetween(-1), maxEnd = getMax(c, d);
    if(b + 1 <= c - 1)
        maxBetween = getMax(b + 1, c - 1);

    if(minStart >= maxEnd || maxBetween >= maxEnd)
        return -1;

    if(a == b && c == d)
        return sub5(a, c);

    return magicFunc(a, b, c, d);
}

#ifdef Nhoksocqt1

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

    #define TASK "jumps"
    if(fopen(TASK".inp", "r")) {
        freopen(TASK".inp", "r", stdin);
        freopen(TASK".out", "w", stdout);
    }

    vector<int> h;
    int n, q;
    cin >> n >> q;

    h.resize(n);
    for (int i = 0; i < n; ++i)
        cin >> h[i];

    init(n, h);
    for (int t = 0; t < q; ++t) {
        int a, b, c, d;
        cin >> a >> b >> c >> d;
        cout << "ANSWER " << a << ' ' << b << ' ' << c << ' ' << d << ": " << minimum_jumps(a, b, c, d) << '\n';
    }

    return 0;
}

#endif // Nhoksocqt1

• Subtask 1: 4 / 4
• Subtask 2: 0 / 8
• Subtask 3: 0 / 13
• Subtask 4: 0 / 12
• Subtask 5: 23 / 23
• Subtask 6: 0 / 21
• Subtask 7: 0 / 19