Submission #569953

#	Time	Username	Problem	Language	Result	Execution time	Memory
569953		drdilyor	Rainforest Jumps (APIO21_jumps)	C++17	60 / 100	4056 ms	44472 KiB

jumps

#if defined(ONPC) && !defined(_GLIBCXX_ASSERTIONS)
    #define _GLIBCXX_ASSERTIONS
#endif
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/detail/standard_policies.hpp>
#include "jumps.h"
#ifdef ONPC
    #include "t_debug.cpp"
#else
    #define debug(...) 42
#endif
#define allit(a) (a).begin(), (a).end()
#define sz(a) ((int) (a).size())

using namespace std;
using ll = long long;
using vi = vector<int>;
namespace pd = __gnu_pbds;
template<typename K>
using ordered_set = pd::tree<K, pd::null_type, less<int>, pd::rb_tree_tag, pd::tree_order_statistics_node_update>;
template<typename... T>
using gp_hash_table = pd::gp_hash_table<T...>;//simple using statement gives warnings

const int INF = 1e9;
const ll INFL = 1e18;
const int N = 200000;
const int LOGN = 19;
const int RANDOM = chrono::high_resolution_clock::now().time_since_epoch().count();
mt19937 rng(RANDOM);

int subtask;

struct SegTree {
    int n;
    vi tree;
    SegTree(int n_) : n(n_), tree(2*n_, INF) {}
    inline void set(int i, int v) {tree[n+i] = min(tree[n+i], v);}
    inline int get(int i) {return tree[n+i];}
    void calc() {
        for (int i = n-1; i >= 1; i--) {
            tree[i] = min(tree[2*i], tree[2*i+1]);
        }
    }
    int query(int l, int r) {
        l += n;
        r += n;
        int res = INF;
        while (l <= r) {
            if (l % 2 == 1) res = min(res, tree[l++]);
            if (r % 2 == 0) res = min(res, tree[r--]);
            l /= 2;
            r /= 2;
        }
        return res;
    }
    void update(int i, int v) {
        tree[n+i] = v;
        for (i = (i+n) / 2; i >= 1; i /= 2) {
            tree[i] = min(tree[2*i], tree[2*i+1]);
        }
    }
    void print() {
        for (int i = n; i < 2*n; i++) {
            if (tree[i] == INF) printf("  #");
            else printf("%3d", tree[i]);
        }
        cout << endl;
    }
};

int next_power2(int i) {
    i--;
    i |= i >> 1;
    i |= i >> 2;
    i |= i >> 4;
    i |= i >> 8;
    i |= i >> 16;
    return 1+i;
}

vector<vi> adj;
int dist[2000][2000];

int dfs(int i, int j) {
    if (i == j) return 0;
    if (dist[i][j] != 0) return dist[i][j];
    int res = INF;
    for (int e : adj[i]) {
        res = min(res, 1+dfs(e, j));
    }
    dist[i][j] = res;
    return res;
}

void init_2_3(int n, vi& h) {
    adj.resize(n);
    vi root(n, 1);
    memset(dist, 0, sizeof(dist));
    for (int i = 0; i < n; i++) {
        int j = i-1, k = i+1;
        for (; j >= 0; j--) {
            if (h[j] > h[i]) break;
        }
        for (; k < n; k++) {
            if (h[k] > h[i]) break;
        }
        if (j >= 0) {
            adj[i].push_back(j);
            root[j] = 0;
        }
        if (k < n) {
            adj[i].push_back(k);
            root[k] = 0;
        }
    }
}

int minimum_jumps_2_3(int a, int b, int c, int d) {
    int res = INF;
    for (int i = a; i <= b; i++) {
        for (int j = c; j <= d; j++) {
            res = min(res, dfs(i, j));
        }
    }
    return (res < INF ? res : -1);
}

vi h;
int st_high[N][LOGN], st_low[N][LOGN];
int to_j;

void init_4_5_6(int n, vi& h_) {
    h = h_;
    to_j = __builtin_ctz(next_power2(n));
    adj.resize(n);
    stack<int> prev;
    for (int i = 0; i < n; i++) {
        while (!prev.empty() && h[prev.top()] < h[i]) {
            adj[prev.top()].push_back(i);
            prev.pop();
        }
        prev.push(i);
    }
    while (!prev.empty()) prev.pop();
    for (int i = n-1; i >= 0; i--) {
        while (!prev.empty() && h[prev.top()] < h[i]) {
            adj[prev.top()].push_back(i);
            prev.pop();
        }
        prev.push(i);
    }
    for (int i = 0; i < n; i++) {
        if (adj[i].size() == 2 && h[adj[i][0]] > h[adj[i][1]]) {
            swap(adj[i][0], adj[i][1]);
        }
    }
    debug(adj);

    for (int i = 0; i < N; i++) {
        for (int j = 0; j < LOGN; j++) {
            st_high[i][j] = st_low[i][j] = -1;
        }
    }

    for (int i = 0; i < n; i++) {
        if (adj[i].size() == 2) {
            st_high[i][0] = adj[i][1];
            st_low[i][0] = adj[i][0];
        } else if (adj[i].size() == 1) {
            st_high[i][0] = st_low[i][0] = adj[i][0];
        }
    }
    for (int j = 1; j <= to_j; j++) {
        for (int i = 0; i + (1 <<j) < n; i++) {
            int next = st_high[i][j-1];
            if (next !=-1)
                st_high[i][j] = st_high[next][j-1];
            next = st_low[i][j-1];
            if (next != -1)
            st_low[i][j] = st_low[ st_low[i][j-1] ][j-1];
        }
    }
}

int minimum_jumps_4(int a, int b, int c, int d) {
    queue<pair<int,int>> q;
    vector<char> visited(adj.size());
    for (int i = a; i <= b; i++) 
        q.push({i, 0});
    int res = -1;
    while (!q.empty()) {
        auto [cur, depth] = q.front();
        q.pop();
        if (c <= cur && cur <= d) {
            res = depth;
            break;
        }
        for (int e : adj[cur])
            if (!visited[e]) {
                q.push({e, depth+1});
                visited[e] = 1;
            }
    }
    return res;
}

int minimum_jumps_5(int a, int b, int c, int d) {
    debug(5);
    assert(a == b);
    assert(c == d);
    int res = 0, cur = a;
    for (int j = to_j; j >= 0; j--) {
        if (st_high[cur][j] != -1 && h[st_high[cur][j]] <= h[c]) {
            res += 1<<j;
            cur = st_high[cur][j];
        }
    }
    for (int j =to_j; j >= 0; j--) {
        if (st_low[cur][j] != -1 && h[st_low[cur][j]] <= h[c]) {
            res += 1<<j;
            cur = st_low[cur][j];
        }
    }
    return cur == d ? res : -1;
}

void init(int n, std::vector<int> h) {
    int inc = 1;
    for (int i = 1; i < n; i++) inc &= h[i-1] < h[i];
    if (inc) {
        subtask = 1;
    } else if (n <= 2000) {
        subtask = 2;
        init_2_3(n, h);
    } else {
        subtask = 4;
        init_4_5_6(n, h);
    }
    debug(subtask);
}

int minimum_jumps(int a, int b, int c, int d) {
    if (subtask == 2)
        return minimum_jumps_2_3(a,b,c,d);
    else if (subtask == 4) {
        if (a == b && c == d)
            return minimum_jumps_5(a,b,c,d);
        else
            return minimum_jumps_4(a,b,c,d);
    }
    else return c - b;
}

Compilation message (stderr)

jumps.cpp: In function 'void init_4_5_6(int, vi&)':
jumps.cpp:11:24: warning: statement has no effect [-Wunused-value]
   11 |     #define debug(...) 42
      |                        ^~
jumps.cpp:158:5: note: in expansion of macro 'debug'
  158 |     debug(adj);
      |     ^~~~~
jumps.cpp: In function 'int minimum_jumps_5(int, int, int, int)':
jumps.cpp:11:24: warning: statement has no effect [-Wunused-value]
   11 |     #define debug(...) 42
      |                        ^~
jumps.cpp:209:5: note: in expansion of macro 'debug'
  209 |     debug(5);
      |     ^~~~~
jumps.cpp: In function 'void init(int, std::vector<int>)':
jumps.cpp:11:24: warning: statement has no effect [-Wunused-value]
   11 |     #define debug(...) 42
      |                        ^~
jumps.cpp:240:5: note: in expansion of macro 'debug'
  240 |     debug(subtask);
      |     ^~~~~

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