Submission #598838

#	Time	Username	Problem	Language	Result	Execution time	Memory
598838		Jomnoi	Rainforest Jumps (APIO21_jumps)	C++17	0 / 100	287 ms	53872 KiB

jumps

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

const int MAX_N = 2e5 + 5;

int N;
int H[MAX_N];
int L[MAX_N], R[MAX_N], J1[MAX_N][20], J2[MAX_N][20], mx[MAX_N][20];
int table[MAX_N][20];

void init(int n, vector <int> h) {
    N = n;
    for(int i = 1; i <= N; i++) {
        H[i] = h[i - 1];
        table[i][0] = H[i];
    }
    H[0] = H[N + 1] = N + 1;

    for(int j = 1; j < 20; j++) {
        for(int i = 1; i + (1<<j) - 1 <= N; i++) {
            table[i][j] = max(table[i][j - 1], table[i + (1<<(j - 1))][j - 1]);
        }
    }

    stack <int> stk;
    stk.push(0);
    for(int i = 1; i <= N; i++) {
        while(!stk.empty() and H[stk.top()] < H[i]) {
            stk.pop();
        }

        L[i] = stk.top();
        stk.push(i);
    }
    while(!stk.empty()) {
        stk.pop();
    }

    stk.push(N + 1);
    for(int i = N; i >= 1; i--) {
        while(!stk.empty() and H[stk.top()] < H[i]) {
            stk.pop();
        }

        R[i] = stk.top();
        stk.push(i);
    }

    L[N + 1] = 0;
    R[0] = N + 1;
    for(int i = 0; i <= N + 1; i++) {
        if(H[L[i]] > H[R[i]]) {
            J1[i][0] = L[i];
            J2[i][0] = R[i];
        }
        else {
            J1[i][0] = R[i];
            J2[i][0] = L[i];
        }
        mx[i][0] = max(L[i], R[i]);
    }

    for(int j = 1; j < 20; j++) {
        for(int i = 0; i <= N + 1; i++) {
            J1[i][j] = J1[J1[i][j - 1]][j - 1];
            J2[i][j] = J2[J2[i][j - 1]][j - 1];
            mx[i][j] = mx[mx[i][j - 1]][j - 1];
        }
    }
}

int get_max(int l, int r) {
    if(l > r) {
        return 0;
    }
    int j = log2(r - l + 1);
    return max(table[l][j], table[r - (1<<j) + 1][j]);
}

int minimum_jumps(int A, int B, int C, int D) {
    A++, B++, C++, D++;

    int lft = get_max(A, B), mid = get_max(B + 1, C - 1), rgh = get_max(C, D);
    if(max(lft, mid) > rgh) {
        return -1;
    }
    if(lft > mid) {
        return 1;
    }

    int l = A, r = B, now = B;
    while(l <= r) {
        int m = (l + r) / 2;
        
        if(H[m] < mid) {
            r = m - 1;
            now = m;
        }
        else {
            l = m + 1;
        }
    }

    int ans = 0;
    for(int i = 19; i >= 0; i--) {
        if(H[J1[now][i]] < rgh and mx[now][i] < C) {
            now = J1[now][i];
            ans += (1<<i);
        }
    }
    if(mx[now][0] >= C) {
        ans++;
        now = mx[now][0];
    }
    else {
        for(int i = 19; i >= 0; i--) {
            if(H[J1[now][i]] < rgh and J2[now][i] < C) {
                now = J2[now][i];
                ans += (1<<i);
            }
        }
        ans++;
        now = J1[now][0];
    }

    if(C <= now and now <= D) {
        return ans;
    }
    return -1;
}

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