| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 569385 | Turkhuu | Rainforest Jumps (APIO21_jumps) | C++17 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include "jumps.h"
#include <bits/stdc++.h>
using namespace std;
const int L = 18;
const int inf = 1000000000;
int n;
vector<int> a;
vector<vector<int>> lo, hi, g;
bool subtask1 = true;
void init(int N, vector<int> H){
n = N, a = H;
g.resize(n);
lo.assign(n, vector(L, -1));
hi.assign(n, vector(L, -1));
for(int i = 1; i < n; i++){
if(a[i - 1] > a[i]){
subtask1 = false;
}
}
vector<int> idx(n);
for(int i = 0; i < n; i++){
idx[--a[i]] = i;
}
set<int> s;
for(int i = n - 1; i >= 0; i--){
auto j = s.lower_bound(idx[i]);
int l = -1, r = -1;
if(j != s.end()){
r = a[*j];
g[idx[i]].push_back(*j);
}
if(j != s.begin()){
l = a[*prev(j)];
g[idx[i]].push_back(*prev(l));
}
if(l != -1 && (r == -1 || l >= r)){
lo[i][0] = r;
hi[i][0] = l;
} else{
lo[i][0] = l;
hi[i][0] = r;
}
s.insert(idx[i]);
}
for(int j = 1; j < L; j++){
for(int i = 0; i < n; i++){
if(lo[i][j - 1] != -1){
lo[i][j] = lo[lo[i][j - 1]][j - 1];
}
if(hi[i][j - 1] != -1){
hi[i][j] = hi[hi[i][j - 1]][j - 1];
}
}
}
}
int minimum_jumps(int A, int B, int C, int D){
if(subtask1){
return C - B;
}
if(A == B && C == D){
int H = a[A], G = a[C], c = 0;
for(int i = L - 1; i >= 0; i--){
if(hi[H][i] != -1 && hi[H][i] <= G){
H = hi[H][i];
c += 1 << i;
}
}
for(int i = L - 1; i >= 0; i--){
if(lo[H][i] != -1 && lo[H][i] <= G){
H = lo[H][i];
c += 1 << i;
}
}
if(H != G){
c = -1;
}
return c;
}
queue<int> q;
vector<int> d(n, inf);
for(int i = A; i <= B; i++){
d[i] = 0;
q.push(i);
}
while(!q.empty()){
int i = q.front();
q.pop();
if(C <= i && i <= D){
return d[i];
}
for(int j : g[i]){
if(d[i] + 1 < d[j]){
d[j] = d[i] + 1;
q.push(j);
}
}
}
return -1;
}