Submission #972523

#	Time	Username	Problem	Language	Result	Execution time	Memory
972523		sleepntsheep	Rainforest Jumps (APIO21_jumps)	C++17	12 / 100	4067 ms	11072 KiB

jumps

#include "jumps.h"

#include <vector>
#include <algorithm>

int subtask = -1;

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

int head[MAX_N], nxt[MAX_M], vv[MAX_M], timer, dd[MAX_N], rt, indeg[MAX_N];

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

void init(int N, std::vector<int> H) {
    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]) link(stk[--so], i);
    so = 0;
    for (int i = N - 1; i >= 0; stk[so++] = i--)
        while (so && H[stk[so-1]] < H[i]) link(stk[--so], i);

    rt = std::min_element(H.begin(), H.end()) - H.begin();
}

int minimum_jumps(int A, int B, int C, int D) {
    if (subtask == 1)
    {
        if (A > D) return -1;
        if (B >= C) return 0;
        return C - B;
    }

    if(subtask <= 3)
    {
        int z = 1e9;
        int dd[3000], qu[3000], qh=0, qt=0;
        for (int i = A; i <= B; ++i)
        {
            qh=qt=0;qu[qh++]=i;
            for(int j=0;j<=3000;++j)dd[j]=1e9;
            dd[i]=0;
            while(qh-qt)
            {
                int u=qu[qt++];
                for(int 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];
        }

        if (z == 1e9) return -1;
        return z;
    }

    return -1;
}

Compilation message (stderr)

jumps.cpp: In function 'int minimum_jumps(int, int, int, int)':
jumps.cpp:55:42: warning: iteration 3000 invokes undefined behavior [-Waggressive-loop-optimizations]
   55 |             for(int j=0;j<=3000;++j)dd[j]=1e9;
      |                                     ~~~~~^~~~
jumps.cpp:55:26: note: within this loop
   55 |             for(int j=0;j<=3000;++j)dd[j]=1e9;
      |                         ~^~~~~~

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