Submission #951315

#	Time	Username	Problem	Language	Result	Execution time	Memory
951315		Nhoksocqt1	Rainforest Jumps (APIO21_jumps)	C++17	100 / 100	842 ms	64888 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;

int seg[4 * MAXN];
int P[MAXN][18], Pn[MAXN][18], Pi[MAXN][18], Pa[MAXN][18];
int h[MAXN], dist[MAXN], nxt[MAXN], prv[MAXN], nTree, nArr;
bool check_sub1;

void build(int id, int l, int r) {
    if(l == r) {
        seg[id] = l;
        return;
    }

    int mid = (l + r) >> 1;
    build(id << 1, l, mid);
    build(id << 1 | 1, mid + 1, r);
    seg[id] = (h[seg[id << 1]] > h[seg[id << 1 | 1]]) ? seg[id << 1] : seg[id << 1 | 1];
}

int findLast(int id, int l, int r, int u, int v, int k) {
    if(u <= l && r <= v) {
        while(l < r) {
            int mid = (l + r) >> 1;
            if(h[seg[id << 1 | 1]] > k) {
                id = id << 1 | 1;
                l = mid + 1;
            } else {
                id = id << 1;
                r = mid;
            }
        }

        return (h[l] > k) ? l + 1 : l;
    }

    int res(0), mid = (l + r) >> 1;
    if(mid + 1 <= v)
        res = findLast(id << 1 | 1, mid + 1, r, u, v, k);

    if(mid >= u && (mid + 1 > v || mid + 1 == res))
        res = findLast(id << 1, l, mid, u, v, k);

    return res;
}

int findFirst(int id, int l, int r, int u, int v, int k) {
    if(u <= l && r <= v) {
        while(l < r) {
            int mid = (l + r) >> 1;
            if(h[seg[id << 1]] > k) {
                id = id << 1;
                r = mid;
            } else {
                id = id << 1 | 1;
                l = mid + 1;
            }
        }

        return l;
    }

    int res(0), mid = (l + r) >> 1;
    if(mid >= u && h[seg[id << 1]] > k)
        res = findFirst(id << 1, l, mid, u, v, k);

    if(mid + 1 <= v && res == 0 && h[seg[id << 1 | 1]] > k)
        res = findFirst(id << 1 | 1, mid + 1, r, u, v, k);

    return res;
}

int query(int id, int l, int r, int u, int v) {
    if(u <= l && r <= v)
        return seg[id];

    int res(0), mid = (l + r) >> 1;
    if(mid >= u)
        res = query(id << 1, l, mid, u, v);

    if(mid + 1 <= v) {
        int qr = query(id << 1 | 1, mid + 1, r, u, v);
        if(res == 0 || h[res] < h[qr])
            res = qr;
    }

    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);
    }

    build(1, 1, nArr);
    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);

    int e = findLast(1, 1, nArr, a, b, maxEnd - 1);
    //int v = findFirst(1, 1, nArr, c, d, maxBetween);
    int u = query(1, 1, nArr, e, b);
    /*cout << "\nH in [a, b] = "; for (int i = a; i <= b; ++i) cout << h[i] << ' '; cout << '\n';
    cout << "H in [c, d] = "; for (int i = c; i <= d; ++i) cout << h[i] << ' '; cout << '\n';
    cout << maxBetween << ' ' << maxEnd << ' ' << e << ' ' << u << ' ' << h[u] << ' ';*/

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

    if(nxt[u] < c && P[u][0] > 0 && nxt[P[u][0]] <= d) {
        u = P[u][0];
        ++res;
    }

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

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

    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 || h[b] >= maxEnd)
        return -1;

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

    //if(brute(a, b, c, d) != magicFunc(a, b, c, d)) exit(1);

    //cout << brute(a, b, c, d) << ' ';
    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];
        h[i] = Random(1, n); cout << h[i] << " \n"[i + 1 == n];
    }

    init(n, h);
    for (int t = 0; t < q; ++t) {
        int a, b, c, d;
        cin >> a >> b >> c >> d;
        //a = Random(0, n - 2), b = Random(a, n - 2), c = Random(b + 1, n - 1), d = Random(c, n - 1);
        cout << "ANSWER " << a << ' ' << b << ' ' << c << ' ' << d << ": " << minimum_jumps(a, b, c, d) << '\n';
    }

    return 0;
}

#endif // Nhoksocqt1

Compilation message (stderr)

jumps.cpp: In function 'int magicFunc(int, int, int, int)':
jumps.cpp:219:9: warning: variable 'maxBetween' set but not used [-Wunused-but-set-variable]
  219 |     int maxBetween(-1), maxEnd = getMax(c, d);
      |         ^~~~~~~~~~

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