// #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(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;
}
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Execution timed out |
1035 ms |
110776 KB |
Time limit exceeded |
| 2 |
Execution timed out |
1037 ms |
126452 KB |
Time limit exceeded |
| 3 |
Execution timed out |
1016 ms |
181404 KB |
Time limit exceeded |
| 4 |
Execution timed out |
1071 ms |
340764 KB |
Time limit exceeded |
| 5 |
Execution timed out |
1074 ms |
491608 KB |
Time limit exceeded |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Execution timed out |
1053 ms |
106152 KB |
Time limit exceeded |
| 2 |
Execution timed out |
1060 ms |
107332 KB |
Time limit exceeded |
| 3 |
Execution timed out |
1065 ms |
114532 KB |
Time limit exceeded |
| 4 |
Execution timed out |
1049 ms |
110108 KB |
Time limit exceeded |
| 5 |
Execution timed out |
1065 ms |
134568 KB |
Time limit exceeded |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Execution timed out |
1084 ms |
110052 KB |
Time limit exceeded |
| 2 |
Execution timed out |
1064 ms |
126100 KB |
Time limit exceeded |
| 3 |
Execution timed out |
1063 ms |
182168 KB |
Time limit exceeded |
| 4 |
Execution timed out |
1065 ms |
339536 KB |
Time limit exceeded |
| 5 |
Execution timed out |
1055 ms |
339524 KB |
Time limit exceeded |
| 6 |
Execution timed out |
1049 ms |
417300 KB |
Time limit exceeded |
| 7 |
Execution timed out |
1039 ms |
418528 KB |
Time limit exceeded |
| 8 |
Execution timed out |
1061 ms |
491520 KB |
Time limit exceeded |
| 9 |
Execution timed out |
1062 ms |
491600 KB |
Time limit exceeded |
| 10 |
Execution timed out |
1031 ms |
491840 KB |
Time limit exceeded |
