#include<iostream>
#include<algorithm>
#include<vector>
#include<set>
using namespace std;
#define ll long long
#define pii pair<ll,ll>
#define mp make_pair
#define endl "\n"
#define out(x) cout<< #x << " = " << x << endl
#define outp(x) cout << #x << " first = " << x.first << " second = " << x.second << endl
#define inf 3e18
int n;
int arr[5005], pos[5005];
int a[5005][5005]; // 預處理,[i,i+1, ... j] 這個區間放在正確位置,會出現幾個逆序
int arev[5005][5005];
int b[5005][5005]; // 預處理,前i個自排列[舊的],第i+1到j個為-1的遞減[新的],舊的和新的之間會產生幾個逆序
int dp[5005];
vector<int> bit(5005);
void init(){
for (int i=1;i<=n;i++) bit[i] = 0;
}
void add(int id,int x){
for (int i=id;i<=n;i+=(i&-i)) bit[i] += x;
}
int sum(int id){
if (id==0) return 0;
int ans = 0;
for (int i=id;i>=1;i-=(i&-i)) ans += bit[i];
return ans;
}
signed main(){
ios::sync_with_stdio(false); cin.tie(0);
cin>>n;
for (int i=1;i<=n;i++) cin>>arr[i], pos[arr[i]] = i;
// precalc a
for (int i=1;i<=n;i++){
init();
for (int j=i;j<=n;j++){
a[i][j] = a[i][j-1] + sum(n) - sum(pos[j]-1);
arev[i][j] = (j-i)*(j-i+1)/2 - a[i][j];
add(pos[j],1);
}
}
// precalc b
for (int i=1;i<=n;i++){
init();
for (int z=1;z<=i;z++) add(pos[z],1);
for (int j=i+1;j<=n;j++){
b[i][j] = b[i][j-1] + i - sum(pos[j]-1);
}
}
// dp[i] = 目前看到前i個位置,逆序最小數量
for (int i=1;i<=n;i++){
dp[i] = 1e9;
for (int j=0;j<i;j++){
dp[i] = min(dp[i], dp[j] + arev[j+1][i] + b[j][i]);
//cout<<i+1<<" "<<j<<" "<<arev[j+1][i]<<endl;
//cout<<i<<" "<<j<<" "<<b[j+1][i]<<endl;
}
}
cout<<dp[n]<<endl;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
332 KB |
Output is correct |
2 |
Correct |
1 ms |
332 KB |
Output is correct |
3 |
Correct |
0 ms |
344 KB |
Output is correct |
4 |
Correct |
1 ms |
348 KB |
Output is correct |
5 |
Correct |
1 ms |
332 KB |
Output is correct |
6 |
Correct |
1 ms |
332 KB |
Output is correct |
7 |
Correct |
1 ms |
332 KB |
Output is correct |
8 |
Correct |
1 ms |
460 KB |
Output is correct |
9 |
Correct |
1 ms |
460 KB |
Output is correct |
10 |
Correct |
1 ms |
460 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
332 KB |
Output is correct |
2 |
Correct |
1 ms |
332 KB |
Output is correct |
3 |
Correct |
0 ms |
344 KB |
Output is correct |
4 |
Correct |
1 ms |
348 KB |
Output is correct |
5 |
Correct |
1 ms |
332 KB |
Output is correct |
6 |
Correct |
1 ms |
332 KB |
Output is correct |
7 |
Correct |
1 ms |
332 KB |
Output is correct |
8 |
Correct |
1 ms |
460 KB |
Output is correct |
9 |
Correct |
1 ms |
460 KB |
Output is correct |
10 |
Correct |
1 ms |
460 KB |
Output is correct |
11 |
Correct |
1 ms |
460 KB |
Output is correct |
12 |
Correct |
1 ms |
588 KB |
Output is correct |
13 |
Correct |
1 ms |
588 KB |
Output is correct |
14 |
Correct |
1 ms |
588 KB |
Output is correct |
15 |
Correct |
1 ms |
588 KB |
Output is correct |
16 |
Correct |
1 ms |
588 KB |
Output is correct |
17 |
Correct |
1 ms |
588 KB |
Output is correct |
18 |
Correct |
1 ms |
588 KB |
Output is correct |
19 |
Correct |
1 ms |
588 KB |
Output is correct |
20 |
Correct |
1 ms |
588 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
332 KB |
Output is correct |
2 |
Correct |
1 ms |
332 KB |
Output is correct |
3 |
Correct |
0 ms |
344 KB |
Output is correct |
4 |
Correct |
1 ms |
348 KB |
Output is correct |
5 |
Correct |
1 ms |
332 KB |
Output is correct |
6 |
Correct |
1 ms |
332 KB |
Output is correct |
7 |
Correct |
1 ms |
332 KB |
Output is correct |
8 |
Correct |
1 ms |
460 KB |
Output is correct |
9 |
Correct |
1 ms |
460 KB |
Output is correct |
10 |
Correct |
1 ms |
460 KB |
Output is correct |
11 |
Correct |
1 ms |
460 KB |
Output is correct |
12 |
Correct |
1 ms |
588 KB |
Output is correct |
13 |
Correct |
1 ms |
588 KB |
Output is correct |
14 |
Correct |
1 ms |
588 KB |
Output is correct |
15 |
Correct |
1 ms |
588 KB |
Output is correct |
16 |
Correct |
1 ms |
588 KB |
Output is correct |
17 |
Correct |
1 ms |
588 KB |
Output is correct |
18 |
Correct |
1 ms |
588 KB |
Output is correct |
19 |
Correct |
1 ms |
588 KB |
Output is correct |
20 |
Correct |
1 ms |
588 KB |
Output is correct |
21 |
Correct |
2 ms |
2892 KB |
Output is correct |
22 |
Correct |
2 ms |
2892 KB |
Output is correct |
23 |
Correct |
2 ms |
2892 KB |
Output is correct |
24 |
Correct |
3 ms |
3020 KB |
Output is correct |
25 |
Correct |
2 ms |
2892 KB |
Output is correct |
26 |
Correct |
3 ms |
3020 KB |
Output is correct |
27 |
Correct |
3 ms |
3020 KB |
Output is correct |
28 |
Correct |
3 ms |
3020 KB |
Output is correct |
29 |
Correct |
3 ms |
3020 KB |
Output is correct |
30 |
Correct |
3 ms |
3020 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
332 KB |
Output is correct |
2 |
Correct |
1 ms |
332 KB |
Output is correct |
3 |
Correct |
0 ms |
344 KB |
Output is correct |
4 |
Correct |
1 ms |
348 KB |
Output is correct |
5 |
Correct |
1 ms |
332 KB |
Output is correct |
6 |
Correct |
1 ms |
332 KB |
Output is correct |
7 |
Correct |
1 ms |
332 KB |
Output is correct |
8 |
Correct |
1 ms |
460 KB |
Output is correct |
9 |
Correct |
1 ms |
460 KB |
Output is correct |
10 |
Correct |
1 ms |
460 KB |
Output is correct |
11 |
Correct |
1 ms |
460 KB |
Output is correct |
12 |
Correct |
1 ms |
588 KB |
Output is correct |
13 |
Correct |
1 ms |
588 KB |
Output is correct |
14 |
Correct |
1 ms |
588 KB |
Output is correct |
15 |
Correct |
1 ms |
588 KB |
Output is correct |
16 |
Correct |
1 ms |
588 KB |
Output is correct |
17 |
Correct |
1 ms |
588 KB |
Output is correct |
18 |
Correct |
1 ms |
588 KB |
Output is correct |
19 |
Correct |
1 ms |
588 KB |
Output is correct |
20 |
Correct |
1 ms |
588 KB |
Output is correct |
21 |
Correct |
2 ms |
2892 KB |
Output is correct |
22 |
Correct |
2 ms |
2892 KB |
Output is correct |
23 |
Correct |
2 ms |
2892 KB |
Output is correct |
24 |
Correct |
3 ms |
3020 KB |
Output is correct |
25 |
Correct |
2 ms |
2892 KB |
Output is correct |
26 |
Correct |
3 ms |
3020 KB |
Output is correct |
27 |
Correct |
3 ms |
3020 KB |
Output is correct |
28 |
Correct |
3 ms |
3020 KB |
Output is correct |
29 |
Correct |
3 ms |
3020 KB |
Output is correct |
30 |
Correct |
3 ms |
3020 KB |
Output is correct |
31 |
Correct |
26 ms |
13728 KB |
Output is correct |
32 |
Correct |
22 ms |
13772 KB |
Output is correct |
33 |
Correct |
23 ms |
13720 KB |
Output is correct |
34 |
Correct |
22 ms |
13768 KB |
Output is correct |
35 |
Correct |
22 ms |
13752 KB |
Output is correct |
36 |
Correct |
23 ms |
13728 KB |
Output is correct |
37 |
Correct |
22 ms |
13764 KB |
Output is correct |
38 |
Correct |
28 ms |
13740 KB |
Output is correct |
39 |
Correct |
27 ms |
13692 KB |
Output is correct |
40 |
Correct |
27 ms |
13716 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
332 KB |
Output is correct |
2 |
Correct |
1 ms |
332 KB |
Output is correct |
3 |
Correct |
0 ms |
344 KB |
Output is correct |
4 |
Correct |
1 ms |
348 KB |
Output is correct |
5 |
Correct |
1 ms |
332 KB |
Output is correct |
6 |
Correct |
1 ms |
332 KB |
Output is correct |
7 |
Correct |
1 ms |
332 KB |
Output is correct |
8 |
Correct |
1 ms |
460 KB |
Output is correct |
9 |
Correct |
1 ms |
460 KB |
Output is correct |
10 |
Correct |
1 ms |
460 KB |
Output is correct |
11 |
Correct |
1 ms |
460 KB |
Output is correct |
12 |
Correct |
1 ms |
588 KB |
Output is correct |
13 |
Correct |
1 ms |
588 KB |
Output is correct |
14 |
Correct |
1 ms |
588 KB |
Output is correct |
15 |
Correct |
1 ms |
588 KB |
Output is correct |
16 |
Correct |
1 ms |
588 KB |
Output is correct |
17 |
Correct |
1 ms |
588 KB |
Output is correct |
18 |
Correct |
1 ms |
588 KB |
Output is correct |
19 |
Correct |
1 ms |
588 KB |
Output is correct |
20 |
Correct |
1 ms |
588 KB |
Output is correct |
21 |
Correct |
2 ms |
2892 KB |
Output is correct |
22 |
Correct |
2 ms |
2892 KB |
Output is correct |
23 |
Correct |
2 ms |
2892 KB |
Output is correct |
24 |
Correct |
3 ms |
3020 KB |
Output is correct |
25 |
Correct |
2 ms |
2892 KB |
Output is correct |
26 |
Correct |
3 ms |
3020 KB |
Output is correct |
27 |
Correct |
3 ms |
3020 KB |
Output is correct |
28 |
Correct |
3 ms |
3020 KB |
Output is correct |
29 |
Correct |
3 ms |
3020 KB |
Output is correct |
30 |
Correct |
3 ms |
3020 KB |
Output is correct |
31 |
Correct |
26 ms |
13728 KB |
Output is correct |
32 |
Correct |
22 ms |
13772 KB |
Output is correct |
33 |
Correct |
23 ms |
13720 KB |
Output is correct |
34 |
Correct |
22 ms |
13768 KB |
Output is correct |
35 |
Correct |
22 ms |
13752 KB |
Output is correct |
36 |
Correct |
23 ms |
13728 KB |
Output is correct |
37 |
Correct |
22 ms |
13764 KB |
Output is correct |
38 |
Correct |
28 ms |
13740 KB |
Output is correct |
39 |
Correct |
27 ms |
13692 KB |
Output is correct |
40 |
Correct |
27 ms |
13716 KB |
Output is correct |
41 |
Correct |
1000 ms |
201152 KB |
Output is correct |
42 |
Correct |
1014 ms |
201200 KB |
Output is correct |
43 |
Correct |
1034 ms |
201252 KB |
Output is correct |
44 |
Correct |
1033 ms |
201284 KB |
Output is correct |
45 |
Correct |
1018 ms |
201220 KB |
Output is correct |
46 |
Correct |
994 ms |
201284 KB |
Output is correct |
47 |
Correct |
1025 ms |
201240 KB |
Output is correct |
48 |
Correct |
987 ms |
201412 KB |
Output is correct |
49 |
Correct |
1006 ms |
201324 KB |
Output is correct |
50 |
Correct |
994 ms |
201272 KB |
Output is correct |
51 |
Correct |
1012 ms |
201324 KB |
Output is correct |
52 |
Correct |
1002 ms |
201336 KB |
Output is correct |
53 |
Correct |
1006 ms |
201332 KB |
Output is correct |
54 |
Correct |
1008 ms |
201344 KB |
Output is correct |
55 |
Correct |
993 ms |
201380 KB |
Output is correct |