Submission #972774

#	Time	Username	Problem	Language	Result	Execution time	Memory
972774		sleepntsheep	Rainforest Jumps (APIO21_jumps)	C++17	4 / 100	1109 ms	15276 KiB

jumps

#include "jumps.h"

#include <vector>
#include <algorithm>

int subtask = -1;

#define MAX_N 200000
#define MAX_M (2*MAX_N)

int N, head[MAX_N], nxt[MAX_M], vv[MAX_M], timer, ng[MAX_N], pg[MAX_N], HI[MAX_N], H[MAX_N];

int dd[MAX_N], pp[MAX_N], jj[MAX_N], dd_[MAX_N], pp_[MAX_N], jj_[MAX_N];

void link(int u, int v)
{
    static int i = 1;
    nxt[i] = head[u];
    vv[i] = v;
    head[u] = i++;
}


void init(int N, std::vector<int> H) {
    ::N = N;
    if (N <= 200) subtask = 2;
    else if (N <= 2000) subtask = 3;
    int flag = 1;
    for (int i = 1; i < N; ++i) if (H[i] != H[i-1] + 1) flag = 0;
    if(flag) subtask = 1;

    static int stk[MAX_N], so;
    so = 0;

    for (int i = 0; i < N; ++i) H[i] = N - H[i] - 1;

    for (int i = 0; i < N; stk[so++] = i++) while (so && H[stk[so-1]] < H[i]) ng[stk[so-1]]=i, link(stk[--so], i);
    while(so)ng[stk[--so]]=-1;
    for (int i = N - 1; i >= 0; stk[so++] = i--) while (so && H[stk[so-1]] < H[i]) pg[stk[so-1]]=i, link(stk[--so], i);
    while(so)pg[stk[--so]]=-1;

    for (int i = 0; i < N; ++i) HI[::H[i]=H[i]] = i;

    for (int j = N; j--;)
    {
        int i = HI[j];
        int high = (pg[i] == -1) ? ng[i] : (ng[i] == -1 ? pg[i] : (H[ng[i]] > H[pg[i]] ? ng[i] : pg[i]));
        if (high != -1)
        {
            dd[i] = dd[high] + 1;
            pp[i] = high;
            jj[i] = dd[high] - dd[jj[high]] == dd[jj[high]] - dd[jj[jj[high]]] ? jj[jj[high]] : high;
        }
        else
            pp[i] = jj[i] = i;
        int low = pg[i] + ng[i] - high;
        if (low != -1)
        {
            dd_[i] = dd_[low] + 1;
            pp_[i] = low;
            jj_[i] = dd_[low] - dd_[jj_[low]] == dd_[jj_[low]] - dd_[jj_[jj_[low]]] ? jj_[jj_[low]] : low;
        }
        else
            pp_[i] = jj_[i] = i;
    }

    if (subtask == -1) subtask = 4;
}

int Q_COUNTER = 0;

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

    if (subtask == 1) return (A>D)?-1:(B>=C?0:C-B);

    std::swap(A, C);
    std::swap(B, D);


    if (subtask == 4 && Q_COUNTER > 5) subtask = 5;

    if(subtask <= 4)
    {
        int dd[MAX_N], qu[MAX_N], qh=0, qt=0,z=1e9;
        for(int j=0;j<N;++j)dd[j]=1e9;
        for (int i = A; i <= B; ++i) dd[qu[qh++]=i]=0;
        while(qh-qt) for(int u=qu[qt++],j=head[u];j;j=nxt[j]) if(dd[vv[j]]>dd[u]+1)dd[vv[j]]=dd[u]+1,qu[qh++]=vv[j];
        for (int j = C; j <= D; ++j)if(dd[j]!=1e9&&dd[j]<z)z=dd[j];
        return(z<1e9?z:-1);
    }

    if (subtask == 5 && A != B) subtask = 6;
    if (subtask == 6 && C != D) subtask = 7;

    if (subtask <= 6)
    {
        int u = A, u1;
        for(;pp[u]!=u;)
        {
            if (H[jj[u]]<=H[C])u=jj[u];
            else if(H[pp[u]]<=H[C])u=pp[u];
            else break;
        }
        u1=u;
        for(;pp_[u]!=u;)
        {
            if(H[jj_[u]]<=H[C])u=jj_[u];
            else if(H[pp_[u]]<=H[C])u=pp_[u];
            else break;
        }
        if(u!=C)return -1;
        return dd_[u1]-dd_[u]+dd[A]-dd[u1];
    }

    return -1;
}

• Subtask 1: 4 / 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