Submission #439040

#	Time	Username	Problem	Language	Result	Execution time	Memory
439040		aris12345678	Rainforest Jumps (APIO21_jumps)	C++14	0 / 100	4051 ms	23484 KiB

jumps

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

const int mxN = 205;
bool sub1 = false;
vector<int> height;
int precomp[mxN][mxN];

int bfs(int i, int end) {
    int n = int(height.size());
    queue<pair<int, int> > q;
    q.push({i, 0});
    while(!q.empty()) {
        int u = q.front().first, jumps = q.front().second;
        q.pop();
        if(u == end)
            return jumps;
        if(height[u] > height[end]) continue;
        int j = u;
        while(j >= 0 && height[j] <= height[u])
            j--;
        // cout << "bfs_1: " << u << " " << j << " " << jumps+1 << "\n";
        if(j >= 0)
            q.push({j, jumps+1});
        j = u;
        while(j < n && height[j] <= height[u])
            j++;
        // cout << "bfs_2: " << u << " " << j << " " << jumps+1 << "\n";
        if(j < n)
            q.push({j, jumps+1});
    }
    return -1;
}

void init(int n, vector<int> h) {
    if(is_sorted(h.begin(), h.end()))
        sub1 = true;
    height = h;
    for(int i = 0; i < n; i++) {
        for(int j = 0; j < n; j++)
            precomp[i][j] = INT_MAX;
    }
    for(int i = 0; i < n; i++) {
        for(int j = i; j < n; j++) {
            if(height[j] < height[i]) continue;
            int jumps = bfs(i, j);
            if(jumps != -1)
                precomp[i][j] = min(precomp[i][j], jumps);
        }
    }
}

int minimum_jumps(int a, int b, int c, int d) {
    if(sub1)
        return c-b;
    else {
        int ans = INT_MAX;
        for(int i = a; i <= b; i++) {
            for(int j = c; j <= d; j++)
                ans = min(ans, precomp[i][j]);
        }
        if(ans == INT_MAX)
            return -1;
        return ans;
    }
}

/*
int main() {
    int n = 7;
    vector<int> h = {3, 2, 1, 6, 4, 5, 7};
    init(n, h);
    int a = 0, b = 1, c = 2, d = 2;
    printf("%d\n", minimum_jumps(a, b, c, d));
    return 0;
}
*/

/*
0 1 2 3 4 5 6
3 2 1 6 4 5 7

(1, 3)
(5, 6)
*/

• 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