Submission #972806

#	Time	Username	Problem	Language	Result	Execution time	Memory
972806		sleepntsheep	Rainforest Jumps (APIO21_jumps)	C++17	81 / 100	770 ms	18412 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], 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];
int dd1[MAX_N],pp1[MAX_N],jj1[MAX_N],ee1[MAX_N];

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

void binlift_connect(int*dd,int*pp,int*jj,int p,int u)
{
    dd[u] = dd[p] + 1;
    pp[u] = p;
    jj[u] = dd[p] - dd[jj[p]] == dd[jj[p]] - dd[jj[jj[p]]] ? jj[jj[p]] : p;
}

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; 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]-1] = 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]));
        int low = pg[i] + ng[i] - high;
        if (high != -1) binlift_connect(dd, pp, jj, high, i);
        else pp[i] = jj[i] = i;
        if (low != -1) binlift_connect(dd_, pp_, jj_, low, i);
        else pp_[i] = jj_[i] = i;
    }

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

    for(int i=0;i<N;++i)
    {
        if(pg[i]==-1) { pp1[i]=jj1[i]=i,dd1[i]=0; }
        else{
            binlift_connect(dd1,pp1,jj1,pg[i],i);
            if(jj1[i]==pp1[i])ee1[i]=H[pg[i]];
            else ee1[i]=std::max(ee1[jj1[pp1[i]]],ee1[pp1[i]]);
        }
    }
}

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);

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

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

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

    if (subtask == 6)
    {
        if(H[B]>H[C])return -1;
        int u=B;
        for(;pp1[u]!=u;)
        {
            if(jj1[u]>=A&&ee1[u]<H[C])u=jj1[u];
            else if(pp1[u]>=A&&H[pp1[u]]<H[C])u=pp1[u];
            else break;
        }
        A=u;
    }

    if (subtask == 5 || subtask == 6)
    {
        if (A==-1)return -1;
        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: 8 / 8
• Subtask 3: 13 / 13
• Subtask 4: 12 / 12
• Subtask 5: 23 / 23
• Subtask 6: 21 / 21
• Subtask 7: 0 / 19