#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const ll INF = 1e9;
ll MOD = 998244353;
typedef pair<ll,ll> ii;
#define iii pair<int,int>
#define f(i,a,b) for(ll i = a;i < b;i++)
#define pb push_back
#define vll vector<ll>
#define F first
#define S second
#define all(x) (x).begin(), (x).end()
///I hope I will get uprating and don't make mistakes
///I will never stop programming
///sqrt(-1) Love C++
///Please don't hack me
///@TheofanisOrfanou Theo830
///Think different approaches (bs,dp,greedy,graphs,shortest paths,mst)
///Stay Calm
///Look for special cases
///Beware of overflow and array bounds
///Think the problem backwards
///Training
///Dremix10 's template
const int N = 2e3+1;
template<typename T>
struct SPARSE{
vector<vector<T> > sparse;
vector<int> log;
const int maxPow = 22;
int N;
void init(int n){
sparse.assign(n,vector<T>(maxPow));
log.assign(n+1,0);
N = n;
for(int i = 2;i <= n;i++)
log[i] = log[i/2] + 1;
}
// supports 0-indexing
void build(T arr[]){
int i,j;
for(i = 0;i < N ;i++)
sparse[i][0] = arr[i];
for(j = 1;j < maxPow;j++)
for(i = 0;i + (1<<j) <= N;i++)
sparse[i][j] = min(sparse[i][j-1],sparse[i+(1<<(j-1))][j-1]);
}
T query(int l, int r){
int k = log[r-l+1];
return min(sparse[l][k],sparse[r-(1<<k)+1][k]);
}
};
template<typename T>
struct SPARSE2{
vector<vector<T> > sparse;
vector<int> log;
const int maxPow = 22;
int N;
void init(int n){
sparse.assign(n,vector<T>(maxPow));
log.assign(n+1,0);
N = n;
for(int i = 2;i <= n;i++)
log[i] = log[i/2] + 1;
}
// supports 0-indexing
void build(T arr[]){
int i,j;
for(i = 0;i < N ;i++)
sparse[i][0] = arr[i];
for(j = 1;j < maxPow;j++)
for(i = 0;i + (1<<j) <= N;i++)
sparse[i][j] = max(sparse[i][j-1],sparse[i+(1<<(j-1))][j-1]);
}
T query(int l, int r){
int k = log[r-l+1];
return max(sparse[l][k],sparse[r-(1<<k)+1][k]);
}
};
SPARSE<ll>s;
SPARSE2<ll>s2;
#include "books.h"
ll dp[1005][1005];
ll n;
ll left[n];
ll right[n];
ll solve(ll i,ll j){
if(i == 0 && j == n-1){
return 0;
}
if(dp[i][j] != -1){
return dp[i][j];
}
ll L = s.query(i,j),R = s2.query(i,j);
if(i == L && j == R){
ll ans = min(solve(i + 1,j) + 2,solve(i,j + 1) + 2);
return dp[i][j] = ans;
}
return dp[i][j] = solve(L,R);
}
long long minimum_walk(std::vector<int> p, int s) {
ll ans = 0;
n = p.size();
bool v[n] = {0};
ll dist = 0;
ll l[n],r[n];
ll L = -1,R;
if(p[s] == s){
L = R = s;
rang.pb(ii(s,s));
}
f(i,0,n){
left[i] = n;
}
f(i,0,n){
if(p[i] != i && !v[i]){
ll last = i;
ll st = i;
ll pos = p[i];
v[i] = 1;
l[st] = i,r[st] = pos;
while(pos != st){
l[st] = min(l[st],pos);
r[st] = max(r[st],pos);
v[pos] = 1;
ans += abs(pos - last);
last = pos;
pos = p[pos];
}
ans += abs(pos - last);
l[st] = min(l[st],pos);
r[st] = max(r[st],pos);
rang.pb(ii(l[st],r[st]));
if(v[s] == 1 && L == -1){
L = l[st];
R = r[st];
}
}
}
if(rang.empty()){
return ans;
}
for(auto x:rang){
left[x.S] = min(left[x.S],x.F);
right[x.F] = max(right[x.F],x.S);
}
s.init(n);
s2.init(n);
s.build(left);
s2.build(right);
memset(dp,-1,sizeof dp);
dist = solve(L,R);
ans += 2 * dist;
return ans;
}
/*
int main() {
int n, s;
assert(2 == scanf("%d %d", &n, &s));
vector<int> p((unsigned) n);
for(int i = 0; i < n; i++)
assert(1 == scanf("%d", &p[(unsigned) i]));
long long res = minimum_walk(p, s);
printf("%lld\n", res);
return 0;
}
*/
/*
4 0
0 2 3 1
*/
Compilation message
books.cpp:98:10: error: array bound is not an integer constant before ']' token
98 | ll left[n];
| ^
books.cpp:99:11: error: array bound is not an integer constant before ']' token
99 | ll right[n];
| ^
books.cpp: In function 'long long int minimum_walk(std::vector<int>, int)':
books.cpp:123:9: error: 'rang' was not declared in this scope; did you mean 'rand'?
123 | rang.pb(ii(s,s));
| ^~~~
| rand
books.cpp:126:15: warning: pointer to a function used in arithmetic [-Wpointer-arith]
126 | left[i] = n;
| ^
books.cpp:126:17: error: assignment of read-only location '*(std::left + ((sizetype)i))'
126 | left[i] = n;
| ~~~~~~~~^~~
books.cpp:146:13: error: 'rang' was not declared in this scope; did you mean 'rand'?
146 | rang.pb(ii(l[st],r[st]));
| ^~~~
| rand
books.cpp:153:8: error: 'rang' was not declared in this scope; did you mean 'rand'?
153 | if(rang.empty()){
| ^~~~
| rand
books.cpp:156:16: error: 'rang' was not declared in this scope; did you mean 'rand'?
156 | for(auto x:rang){
| ^~~~
| rand
books.cpp:160:7: error: request for member 'init' in 's', which is of non-class type 'int'
160 | s.init(n);
| ^~~~
books.cpp:162:7: error: request for member 'build' in 's', which is of non-class type 'int'
162 | s.build(left);
| ^~~~~
books.cpp:163:14: error: cannot convert 'std::ios_base&(std::ios_base&)' to 'long long int*'
163 | s2.build(right);
| ^~~~~
| |
| std::ios_base&(std::ios_base&)
books.cpp:77:18: note: initializing argument 1 of 'void SPARSE2<T>::build(T*) [with T = long long int]'
77 | void build(T arr[]){
| ~~^~~~~
