#pragma GCC target( "sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#pragma GCC optimize("Ofast,unroll-loops,fast-math,O3")
#include<bits/stdc++.h>
#define f first
#define s second
#define pb push_back
#define sz(x) (int)x.size()
#define bit(a, i) ((a>>i)&1)
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
const int P = 31;
const int K = 400;
const ll inf = 1e9;
const ll INF = 1e18;
const int mod = 1e9+7;
const int maxn = 5e3 + 10;
const int dx[] = {0, 0, -1, 1};
const int dy[] = {1, -1, 0, 0};
int n;
int a[maxn];
ll d[2][maxn][maxn];
int main(){
ios_base::sync_with_stdio(0);
cin.tie(0); cout.tie(0);
cin >> n;
for(int i=1; i<=n; i++){
cin >> a[i];
fill(d[0][i], d[0][i]+n+1, INF);
fill(d[1][i], d[1][i]+n+1, INF);
}
d[0][2][n] = d[1][1][n] = 0;
priority_queue<pair<pair<ll, int>, pii>>q;
q.push({{0, 0}, {2, n}});
q.push({{0, 1}, {1, n}});
while(sz(q)){
int l = q.top().s.f;
int r = q.top().s.s;
int tp = q.top().f.s;
ll val = -q.top().f.f;
q.pop();
if(l == r) continue;
if(val > d[tp][l][r]) continue;
if(tp){
if(l&1){
int R = r;
if(a[r-1] > a[r]) R--;
int mn = min(a[l+1], a[R]);
ll sum = d[1][l][r]+mn-a[l];
if(l<n){
if(a[l+1] == mn && d[1][l+1][r] > sum){
d[1][l+1][r] = sum;
q.push({{-d[1][l+1][r], 1}, {l+1, r}});
}
if(a[R] == mn && d[0][l+1][R] > sum){
d[0][l+1][R] = sum;
q.push({{-d[0][l+1][R], 0}, {l+1, R}});
}} if(l<2) continue;
mn = min(a[l-1], a[R]);
sum = d[1][l][r]+mn-a[l];
if(a[l-1] == mn && d[1][l-1][r] > sum){
d[1][l-1][r] = sum;
q.push({{-d[1][l-1][r], 1}, {l-1, r}});
}
if(a[R] == mn && d[0][l][R] > sum){
d[0][l][R] = sum;
q.push({{-d[0][l][R], 0}, {l, R}});
}
} else{
int R = r;
if(a[r-1] < a[r]) R--;
int mx = max(a[l+1], a[R]);
ll sum = d[1][l][r]+a[l]-mx;
if(l<n){if(a[l+1] == mx && d[1][l+1][r] > sum){
d[1][l+1][r] = sum;
q.push({{-d[1][l+1][r], 1}, {l+1, r}});
}
if(a[R] == mx && d[0][l+1][R] > sum){
d[0][l+1][R] = sum;
q.push({{-d[0][l+1][R], 0}, {l+1, R}});
}} if(l<2) continue;
mx = max(a[l-1], a[R]);
sum = d[1][l][r]+a[l]-mx;
if(a[l-1] == mx && d[1][l-1][r] > sum){
d[1][l-1][r] = sum;
q.push({{-d[1][l-1][r], 1}, {l-1, r}});
}
if(a[R] == mx && d[0][l][R] > sum){
d[0][l][R] = sum;
q.push({{-d[0][l][R], 0}, {l, R}});
}
}
} else{
if(r&1){
int L = l;
if(a[l-1]>a[l]) L--;
int mn = min(a[r+1], a[L]);
ll sum = d[0][l][r]+mn-a[r];
if(r<n){
if(a[r+1] == mn && d[0][l][r+1] > sum){
d[0][l][r+1] = sum;
q.push({{-d[0][l][r+1], 0}, {l, r+1}});
}
if(a[L] == mn && d[1][L][r+1] > sum){
d[1][L][r+1] = sum;
q.push({{-d[1][L][r+1], 1}, {L, r+1}});
}
} if(r<2) continue;
mn = min(a[r-1], a[L]);
sum = d[0][l][r]+mn-a[r];
if(a[r-1] == mn && d[0][l][r-1] > sum){
d[0][l][r-1] = sum;
q.push({{-d[0][l][r-1], 0}, {l, r-1}});
}
if(a[L] == mn && d[1][L][r] > sum){
d[1][L][r] = sum;
q.push({{-d[1][L][r], 1}, {L, r}});
}
} else{
int L = l;
if(a[l-1]<a[l]) L--;
int mx = max(a[r+1], a[L]);
ll sum = d[0][l][r]+a[r]-mx;
if(r<n){
if(a[r+1] == mx && d[0][l][r+1] > sum){
d[0][l][r+1] = sum;
q.push({{-d[0][l][r+1], 0}, {l, r+1}});
}
if(a[L] == mx && d[1][L][r+1] > sum){
d[1][L][r+1] = sum;
q.push({{-d[1][L][r+1], 1}, {L, r+1}});
}
} if(r<2) continue;
mx = max(a[r-1], a[L]);
sum = d[0][l][r]+a[r]-mx;
if(a[r-1] == mx && d[0][l][r-1] > sum){
d[0][l][r-1] = sum;
q.push({{-d[0][l][r-1], 0}, {l, r-1}});
}
if(a[L] == mx && d[1][L][r] > sum){
d[1][L][r] = sum;
q.push({{-d[1][L][r], 1}, {L, r}});
}
}
}
}
ll ans = INF;
for(int i=1; i<=n; i++){
ans = min(ans, d[0][i][i]);
ans = min(ans, d[1][i][i]);
} if(ans == INF) cout << "NO\n";
else cout << ans;
}
Compilation message
In file included from /usr/include/x86_64-linux-gnu/c++/10/bits/gthr.h:148,
from /usr/include/c++/10/ext/atomicity.h:35,
from /usr/include/c++/10/bits/ios_base.h:39,
from /usr/include/c++/10/ios:42,
from /usr/include/c++/10/istream:38,
from /usr/include/c++/10/sstream:38,
from /usr/include/c++/10/complex:45,
from /usr/include/c++/10/ccomplex:39,
from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:54,
from climbers.cpp:3:
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:102:1: error: attribute value 'tune=native' was already specified in 'target' attribute
102 | __gthrw(pthread_once)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:102:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:103:1: error: attribute value 'tune=native' was already specified in 'target' attribute
103 | __gthrw(pthread_getspecific)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:103:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:104:1: error: attribute value 'tune=native' was already specified in 'target' attribute
104 | __gthrw(pthread_setspecific)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:104:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:106:1: error: attribute value 'tune=native' was already specified in 'target' attribute
106 | __gthrw(pthread_create)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:106:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:107:1: error: attribute value 'tune=native' was already specified in 'target' attribute
107 | __gthrw(pthread_join)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:107:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:108:1: error: attribute value 'tune=native' was already specified in 'target' attribute
108 | __gthrw(pthread_equal)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:108:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:109:1: error: attribute value 'tune=native' was already specified in 'target' attribute
109 | __gthrw(pthread_self)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:109:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:110:1: error: attribute value 'tune=native' was already specified in 'target' attribute
110 | __gthrw(pthread_detach)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:110:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:112:1: error: attribute value 'tune=native' was already specified in 'target' attribute
112 | __gthrw(pthread_cancel)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:112:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:114:1: error: attribute value 'tune=native' was already specified in 'target' attribute
114 | __gthrw(sched_yield)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:114:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:116:1: error: attribute value 'tune=native' was already specified in 'target' attribute
116 | __gthrw(pthread_mutex_lock)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:116:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:117:1: error: attribute value 'tune=native' was already specified in 'target' attribute
117 | __gthrw(pthread_mutex_trylock)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:117:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:119:1: error: attribute value 'tune=native' was already specified in 'target' attribute
119 | __gthrw(pthread_mutex_timedlock)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:119:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:121:1: error: attribute value 'tune=native' was already specified in 'target' attribute
121 | __gthrw(pthread_mutex_unlock)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:121:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:122:1: error: attribute value 'tune=native' was already specified in 'target' attribute
122 | __gthrw(pthread_mutex_init)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:122:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:123:1: error: attribute value 'tune=native' was already specified in 'target' attribute
123 | __gthrw(pthread_mutex_destroy)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:123:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:125:1: error: attribute value 'tune=native' was already specified in 'target' attribute
125 | __gthrw(pthread_cond_init)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:125:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:126:1: error: attribute value 'tune=native' was already specified in 'target' attribute
126 | __gthrw(pthread_cond_broadcast)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:126:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:127:1: error: attribute value 'tune=native' was already specified in 'target' attribute
127 | __gthrw(pthread_cond_signal)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:127:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:128:1: error: attribute value 'tune=native' was already specified in 'target' attribute
128 | __gthrw(pthread_cond_wait)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:128:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:129:1: error: attribute value 'tune=native' was already specified in 'target' attribute
129 | __gthrw(pthread_cond_timedwait)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:129:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:130:1: error: attribute value 'tune=native' was already specified in 'target' attribute
130 | __gthrw(pthread_cond_destroy)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:130:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:132:1: error: attribute value 'tune=native' was already specified in 'target' attribute
132 | __gthrw(pthread_key_create)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:132:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:133:1: error: attribute value 'tune=native' was already specified in 'target' attribute
133 | __gthrw(pthread_key_delete)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:133:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:134:1: error: attribute value 'tune=native' was already specified in 'target' attribute
134 | __gthrw(pthread_mutexattr_init)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:134:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:135:1: error: attribute value 'tune=native' was already specified in 'target' attribute
135 | __gthrw(pthread_mutexattr_settype)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:135:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:136:1: error: attribute value 'tune=native' was already specified in 'target' attribute
136 | __gthrw(pthread_mutexattr_destroy)
| ^~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:136:1: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:237:10: error: attribute value 'tune=native' was already specified in 'target' attribute
237 | __gthrw2(__gthrw_(__pthread_key_create),
| ^~~~~~~~
/usr/include/x86_64-linux-gnu/c++/10/bits/gthr-default.h:237:10: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/c++/10/shared_mutex:73:3: error: attribute value 'tune=native' was already specified in 'target' attribute
73 | _GLIBCXX_GTHRW(rwlock_rdlock)
| ^~~~~~~~~~~~~~
/usr/include/c++/10/shared_mutex:73:3: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/c++/10/shared_mutex:74:3: error: attribute value 'tune=native' was already specified in 'target' attribute
74 | _GLIBCXX_GTHRW(rwlock_tryrdlock)
| ^~~~~~~~~~~~~~
/usr/include/c++/10/shared_mutex:74:3: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/c++/10/shared_mutex:75:3: error: attribute value 'tune=native' was already specified in 'target' attribute
75 | _GLIBCXX_GTHRW(rwlock_wrlock)
| ^~~~~~~~~~~~~~
/usr/include/c++/10/shared_mutex:75:3: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/c++/10/shared_mutex:76:3: error: attribute value 'tune=native' was already specified in 'target' attribute
76 | _GLIBCXX_GTHRW(rwlock_trywrlock)
| ^~~~~~~~~~~~~~
/usr/include/c++/10/shared_mutex:76:3: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/c++/10/shared_mutex:77:3: error: attribute value 'tune=native' was already specified in 'target' attribute
77 | _GLIBCXX_GTHRW(rwlock_unlock)
| ^~~~~~~~~~~~~~
/usr/include/c++/10/shared_mutex:77:3: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/c++/10/shared_mutex:91:4: error: attribute value 'tune=native' was already specified in 'target' attribute
91 | __gthrw(pthread_rwlock_timedrdlock);
| ^~~~~~~
/usr/include/c++/10/shared_mutex:91:4: error: attribute value 'tune=native' was already specified in 'target' attribute
/usr/include/c++/10/shared_mutex:101:4: error: attribute value 'tune=native' was already specified in 'target' attribute
101 | __gthrw(pthread_rwlock_timedwrlock);
| ^~~~~~~
/usr/include/c++/10/shared_mutex:101:4: error: attribute value 'tune=native' was already specified in 'target' attribute
