Submission #972509

#	Time	Username	Problem	Language	Result	Execution time	Memory
972509		sleepntsheep	Rainforest Jumps (APIO21_jumps)	C++17	4 / 100	552 ms	18380 KiB

jumps

#include "jumps.h"

#include <vector>

int subtask = -1;

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

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

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

void dfs(int u)
{
    tin[u] = timer++;
    for (int j = head[u]; j; j = nxt[j]) dd[vv[j]] = dd[u] + 1, dfs(vv[j]);
    tout[u] = timer - 1;
}

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);
    for (int i = 0; i < N; ++i)
        if (indeg[i] == 0) rt = i;

    dfs(rt);
}

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;
    }

    int z  = 1e9;
    for (int i = A; i <= B; ++i)
        for (int j = C; j <= D; ++j)
            if (tin[i] <= tin[j] && tout[j] <= tout[i] && dd[i] - dd[j] < z) z = dd[i] - dd[j];

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

• 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