| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 567358 | amunduzbaev | 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"
#ifndef EVAL
#include "stub.cpp"
#endif
#include "bits/stdc++.h"
using namespace std;
const int B = 1000;
const int N = 2e5 + 5;
const int M = N / B + 2;
const int lg = 18;
vector<int> edges[N];
int mx[N][lg], mn[N][lg], h[N], pos[N];
int st[N][lg], pre[N];
int lx[N], rx[N];
struct ST{
int tree[N][lg];
void build(){
for(int i=0;i<N;i++) tree[i][0] = pre[i];
for(int j=1;j<lg;j++){
for(int i=0;i + (1 << (j - 1))<N;i++){
tree[i][j] = min(tree[i][j-1], tree[i + (1 << (j - 1))][j-1]);
}
}
}
int get(int l, int r){
int lg = __lg(r - l + 1);
return min(tree[l][lg], tree[r - (1 << lg) + 1][lg]);
}
}tree[M];
void init(int n, vector<int> H){
for(int i=0;i<n;i++){
h[i] = H[i];
pos[h[i]] = i;
st[i][0] = h[i];
}
vector<int> ss;
for(int i=0;i<n;i++){
while(!ss.empty() && h[ss.back()] < h[i]) ss.pop_back();
if(!ss.empty()) lx[i] = ss.back();
else lx[i] = n;
ss.push_back(i);
} ss.clear();
for(int i=n-1;~i;i--){
while(!ss.empty() && h[ss.back()] < h[i]) ss.pop_back();
if(!ss.empty()) rx[i] = ss.back();
else rx[i] = n;
ss.push_back(i);
} ss.clear();
h[n] = N;
for(int i=0;i<n;i++){
if(h[lx[i]] < h[rx[i]]){
swap(lx[i], rx[i]);
}
edges[lx[i]].push_back(i);
edges[rx[i]].push_back(i);
mn[i][0] = rx[i];
mx[i][0] = lx[i];
lx[i] = min(lx[i], rx[i]);
if(i < lx[i]) lx[i] = -1;
}
mn[n][0] = mx[n][0] = n;
edges[n].clear();
for(int b=0;b * B<n;b++){
memset(pre, 127, sizeof pre);
queue<int> q;
for(int i=0;b * B + i<n && i<B;i++){
q.push(b * B + i);
pre[b * B + i] = 0;
}
while(!q.empty()){
int u = q.front(); q.pop();
for(auto x : edges[u]){
if(pre[x] > pre[u] + 1){
pre[x] = pre[u] + 1;
q.push(x);
}
}
}
tree[b].build();
}
for(int j=1;j<lg;j++){
for(int i=0;i<=n;i++){
if(i + (1 << (j - 1)) < n) st[i][j] = max(st[i][j - 1], st[i + (1 << (j - 1))][j-1]);
mn[i][j] = mn[mn[i][j-1]][j-1];
mx[i][j] = mx[mx[i][j-1]][j-1];
}
}
}
int get(int l, int r){
int lg = __lg(r - l + 1);
return max(st[l][lg], st[r - (1 << lg) + 1][lg]);
}
int check(int a, int c){
int res = 0;
for(int i=lg-1;~i;i--){
if(h[mx[a][i]] <= h[c]){
//~ cout<<mx[a][i]<<" "<<h[mx[a][i]]<<" "<<h[c]<<"\n";
//~ cout<<i<<"\n";
a = mx[a][i], res += (1 << i);
}
}
for(int i=lg-1;~i;i--){
if(h[mn[a][i]] <= h[c]){
//~ cout<<mx[a][i]<<" "<<h[mx[a][i]]<<" "<<h[c]<<"\n";
a = mn[a][i], res += (1 << i);
}
}
if(a != c) return N;
return res;
}
int minimum_jumps(int a, int b, int c, int d) {
int bl = c / B, br = d / B;
int res = N;
for(int j=bl+1;j<br;j++){
//~ assert(false);
res = min(res, tree[j].get(a, b));
}
auto calc = [&](int l, int r){
for(int i=l;i<=r;i++){
int L = max(lx[i] + 1, a);
if(L <= b){
int mx = pos[get(L, b)];
res = min(res, check(mx, i));
}
}
};
if(bl == br){
calc(c, d);
} else {
if(c % B == 0) res = min(res, tree[bl].get(a, b));
else calc(c, (bl + 1) * B - 1);
if((d + 1) % B == 0) res = min(res, tree[br].get(a, b));
else calc(br * B, d);
}
if(res == N) return -1;
return res;
}
/*
7 2
3 2 1 6 4 5 7
4 4 6 6
0 1 2 2
*/