Submission #467756

#	Time	Username	Problem	Language	Result	Execution time	Memory
467756		spike1236	Rainforest Jumps (APIO21_jumps)	C++14	81 / 100	4091 ms	56768 KiB

jumps

#include <bits/stdc++.h>
using namespace std;
#define pb push_back
#define mp make_pair
#define f first
#define s second
#define ll long long
#define ld long double
#define all(_v) _v.begin(), _v.end()
#define sz(_v) (int)_v.size()
#define pii pair <int, int>
#define pll pair <ll, ll>
#define veci vector <int>
#define vecll vector <ll>

const int dx[4] = {1, -1, 0, 0};
const int dy[4] = {0, 0, -1, 1};
const double PI = 3.1415926535897932384626433832795;
const double eps = 1e-9;
const int MOD1 = 1e9 + 7;
const int MOD2 = 998244353;

const int MAXN = 2e5 + 10;
int a[MAXN];
int L[MAXN], R[MAXN];
int n;
bool issorted;
int up_L[MAXN][22], up_R[MAXN][22], up_h[MAXN][22];
int dist[MAXN];

void init(int _n, veci _a) {
    n = _n;
    for(int i = 0; i < _n; ++i) a[i + 1] = _a[i];
    issorted = 1;
    for(int i = 1; i <= n; ++i)
        issorted &= (a[i] == 1 + a[i - 1]);
    a[0] = a[n + 1] = n + 1;
    stack <int> st;
    for(int i = 1; i <= n; ++i) {
        while(!st.empty() && a[st.top()] < a[i]) st.pop();
        if(!st.empty()) L[i] = st.top();
        else L[i] = 0;
        st.push(i);
    }
    while(!st.empty()) st.pop();
    for(int i = n; i > 0; --i) {
        while(!st.empty() && a[st.top()] < a[i]) st.pop();
        if(!st.empty()) R[i] = st.top();
        else R[i] = n + 1;
        st.push(i);
    }
    for(int i = 1; i <= n; ++i) {
        up_L[i][0] = L[i];
        up_R[i][0] = R[i];
        up_h[i][0] = (a[L[i]] > a[R[i]] ? L[i] : R[i]);
    }
    for(int j = 1; j < 20; ++j) {
        for(int i = 1; i <= n; ++i) {
            up_L[i][j] = up_L[up_L[i][j - 1]][j - 1];
            up_R[i][j] = up_R[up_R[i][j - 1]][j - 1];
            up_h[i][j] = up_h[up_h[i][j - 1]][j - 1];
        }
    }
}

int minimum_jumps_eq(int l, int x) {
    int ans = 0;
    for(int i = 19; i >= 0; --i)
        if(a[up_h[l][i]] <= a[x]) l = up_h[l][i], ans += (1 << i);
    if(a[L[l]] > a[x]) {
        for(int i = 19; i >= 0; --i)
            if(a[up_R[l][i]] <= a[x]) l = up_R[l][i], ans += (1 << i);
    } else {
        for(int i = 19; i <= 0; --i)
            if(a[up_L[l][i]] <= a[x]) l = up_L[l][i], ans += (1 << i);
    }
    return (l == x ? ans : -1);
}

int minimum_jumps(int l, int r, int x, int y) {
    ++l, ++r, ++x, ++y;
    if(issorted) return x - r;
    if(x == y) {
        for(int i = 19; i >= 0; --i)
            if(up_L[r][i] >= l && a[up_L[r][i]] < a[x]) r = up_L[r][i];
        return minimum_jumps_eq(r, x);
    }
    queue <int> q;
    for(int i = 1; i <= n; ++i) dist[i] = 1e9;
    for(int i = l; i <= r; ++i) {
        q.push(i);
        dist[i] = 0;
    }
    while(!q.empty()) {
        int v = q.front();
        q.pop();
        if(dist[L[v]] > dist[v] + 1) {
            dist[L[v]] = dist[v] + 1;
            q.push(L[v]);
        }
        if(dist[R[v]] > dist[v] + 1) {
            dist[R[v]] = dist[v] + 1;
            q.push(R[v]);
        }
    }
    int ans = 1e9;
    for(int i = x; i <= y; ++i) ans = min(ans, dist[i]);
    return (ans == 1e9 ? -1 : ans);
}

• 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: 0 / 19