oj.uz

Submission #379555

# Submission time Handle Problem Language Result Execution time Memory
379555 2021-03-18T14:48:57 Z socho Group Photo (JOI21_ho_t3) C++14
100 / 100
 1711 ms 134892 KB 
// upsolve, inspired by @smjleo code
#include <bits/stdc++.h>
using namespace std;
void fast() {
	ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
}
void ran() {
	srand(chrono::steady_clock::now().time_since_epoch().count());
}
long long get_rand() {
	long long a = rand();
	long long b = rand();
	return a * (RAND_MAX + 1ll) + b;
}
void usaco() {
	freopen("problem.in", "r", stdin); 
	freopen("problem.out", "w", stdout);
}
template<typename T>
using min_pq = priority_queue<T, vector<T>, greater<T>>;
// #define endl '\n'
// #define double long double
// #define int long long
// const int MOD = 1000 * 1000 * 1000 + 7;
// const int MOD = 998244353;

const int MXN = 5005;
int n;
int arr[MXN];
int pos[MXN];
int dp[MXN];
vector<int> rgs;

int cost[MXN][MXN];
int iv[MXN][MXN];
int before[MXN];
int herepos[MXN];


int fw[MXN*2];
void update(int x, int v) {
    for (; x<MXN*2; x+=x&(-x)) fw[x] += v; 
}
int sum(int x) {
    int res = 0;
    for(; x; x-=x&(-x)) res += fw[x];
    return res;
}

int fw2[MXN*2];
void update2(int x, int v) {
    for (; x<MXN*2; x+=x&(-x)) fw2[x] += v; 
}
int sum2(int x) {
    int res = 0;
    for(; x; x-=x&(-x)) res += fw2[x];
    return res;
}

void solverow(int L) {
	
	// only values >= L exist
	
	// find all cost[L][x]
	
	int curr = 0;
	for (auto x: rgs) {
		before[x] = curr;
		curr++;
		herepos[x] = curr;
	}
	
	memset(fw, 0, sizeof fw);
	
	for (int x=L; x<=n; x++) {
		// for each [L][x], how many inversions in this range?
		// when i add a new x, the number of inversions increases by the number of values before x and smaller than x
		// also increases by number of values after x and larger than x
		iv[L][x] = iv[L][x-1];
		// now i add item x
		// all previous items which are before it are a new inversion
		iv[L][x] += sum(pos[x]);
		update(pos[x], 1);
	}
	
	memset(fw2, 0, sizeof fw2);
	memset(fw, 0, sizeof fw);
	
	for (int i=L; i<=n; i++) {
		update2(before[i]+1, 1);
	}
	
	int tcost = 0;
	for (int i=n; i>=L; i--) {
		cost[L][i] = iv[L][i] + tcost;
		tcost -= sum(before[i]+1);
		update(before[i]+1, 1);
		update2(before[i]+1, -1);
		tcost += sum2(n) - sum2(before[i]+1);
	}
	
}

signed main() {

	ran(); fast();

	cin >> n;
	for (int i=1; i<=n; i++) {
		cin >> arr[i];
		pos[arr[i]] = i;
	}
	
	for (int i=1; i<=n; i++) {
		rgs.clear();
		for (int j=1; j<=n; j++) {
			if (arr[j] >= i) rgs.push_back(arr[j]);
		}
		solverow(i);
	}

	for (int i=1; i<=n; i++) {
		
		// solve first i positions
		dp[i] = INT_MAX / 2;
		
		for (int j=1; j<=i; j++) {
			
			// j..i are in reverse, + dp[j-1]
			dp[i] = min(dp[i], dp[j-1] + cost[j][i]);
			
		}
		
	}
	
	cout << dp[n] << endl;

}

Compilation message

Main.cpp: In function 'void usaco()':
Main.cpp:16:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   16 |  freopen("problem.in", "r", stdin);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:17:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   17 |  freopen("problem.out", "w", stdout);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 492 KB Output is correct
2 Correct 1 ms 492 KB Output is correct
3 Correct 1 ms 492 KB Output is correct
4 Correct 1 ms 492 KB Output is correct
5 Correct 1 ms 492 KB Output is correct
6 Correct 1 ms 512 KB Output is correct
7 Correct 1 ms 504 KB Output is correct
8 Correct 1 ms 492 KB Output is correct
9 Correct 1 ms 492 KB Output is correct
10 Correct 1 ms 492 KB Output is correct

Subtask #2
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 492 KB Output is correct
2 Correct 1 ms 492 KB Output is correct
3 Correct 1 ms 492 KB Output is correct
4 Correct 1 ms 492 KB Output is correct
5 Correct 1 ms 492 KB Output is correct
6 Correct 1 ms 512 KB Output is correct
7 Correct 1 ms 504 KB Output is correct
8 Correct 1 ms 492 KB Output is correct
9 Correct 1 ms 492 KB Output is correct
10 Correct 1 ms 492 KB Output is correct
11 Correct 1 ms 620 KB Output is correct
12 Correct 1 ms 620 KB Output is correct
13 Correct 1 ms 620 KB Output is correct
14 Correct 1 ms 620 KB Output is correct
15 Correct 1 ms 620 KB Output is correct
16 Correct 1 ms 620 KB Output is correct
17 Correct 1 ms 768 KB Output is correct
18 Correct 1 ms 620 KB Output is correct
19 Correct 1 ms 620 KB Output is correct
20 Correct 1 ms 620 KB Output is correct

Subtask #3
32.0 / 32.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 492 KB Output is correct
2 Correct 1 ms 492 KB Output is correct
3 Correct 1 ms 492 KB Output is correct
4 Correct 1 ms 492 KB Output is correct
5 Correct 1 ms 492 KB Output is correct
6 Correct 1 ms 512 KB Output is correct
7 Correct 1 ms 504 KB Output is correct
8 Correct 1 ms 492 KB Output is correct
9 Correct 1 ms 492 KB Output is correct
10 Correct 1 ms 492 KB Output is correct
11 Correct 1 ms 620 KB Output is correct
12 Correct 1 ms 620 KB Output is correct
13 Correct 1 ms 620 KB Output is correct
14 Correct 1 ms 620 KB Output is correct
15 Correct 1 ms 620 KB Output is correct
16 Correct 1 ms 620 KB Output is correct
17 Correct 1 ms 768 KB Output is correct
18 Correct 1 ms 620 KB Output is correct
19 Correct 1 ms 620 KB Output is correct
20 Correct 1 ms 620 KB Output is correct
21 Correct 5 ms 2156 KB Output is correct
22 Correct 5 ms 2156 KB Output is correct
23 Correct 5 ms 2156 KB Output is correct
24 Correct 5 ms 2156 KB Output is correct
25 Correct 5 ms 2156 KB Output is correct
26 Correct 5 ms 2156 KB Output is correct
27 Correct 5 ms 2156 KB Output is correct
28 Correct 5 ms 2156 KB Output is correct
29 Correct 5 ms 2156 KB Output is correct
30 Correct 5 ms 2156 KB Output is correct

Subtask #4
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 492 KB Output is correct
2 Correct 1 ms 492 KB Output is correct
3 Correct 1 ms 492 KB Output is correct
4 Correct 1 ms 492 KB Output is correct
5 Correct 1 ms 492 KB Output is correct
6 Correct 1 ms 512 KB Output is correct
7 Correct 1 ms 504 KB Output is correct
8 Correct 1 ms 492 KB Output is correct
9 Correct 1 ms 492 KB Output is correct
10 Correct 1 ms 492 KB Output is correct
11 Correct 1 ms 620 KB Output is correct
12 Correct 1 ms 620 KB Output is correct
13 Correct 1 ms 620 KB Output is correct
14 Correct 1 ms 620 KB Output is correct
15 Correct 1 ms 620 KB Output is correct
16 Correct 1 ms 620 KB Output is correct
17 Correct 1 ms 768 KB Output is correct
18 Correct 1 ms 620 KB Output is correct
19 Correct 1 ms 620 KB Output is correct
20 Correct 1 ms 620 KB Output is correct
21 Correct 5 ms 2156 KB Output is correct
22 Correct 5 ms 2156 KB Output is correct
23 Correct 5 ms 2156 KB Output is correct
24 Correct 5 ms 2156 KB Output is correct
25 Correct 5 ms 2156 KB Output is correct
26 Correct 5 ms 2156 KB Output is correct
27 Correct 5 ms 2156 KB Output is correct
28 Correct 5 ms 2156 KB Output is correct
29 Correct 5 ms 2156 KB Output is correct
30 Correct 5 ms 2156 KB Output is correct
31 Correct 44 ms 9324 KB Output is correct
32 Correct 44 ms 9452 KB Output is correct
33 Correct 45 ms 9452 KB Output is correct
34 Correct 44 ms 9452 KB Output is correct
35 Correct 44 ms 9452 KB Output is correct
36 Correct 45 ms 9452 KB Output is correct
37 Correct 45 ms 9580 KB Output is correct
38 Correct 44 ms 9472 KB Output is correct
39 Correct 44 ms 9464 KB Output is correct
40 Correct 44 ms 9452 KB Output is correct

Subtask #5
36.0 / 36.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 492 KB Output is correct
2 Correct 1 ms 492 KB Output is correct
3 Correct 1 ms 492 KB Output is correct
4 Correct 1 ms 492 KB Output is correct
5 Correct 1 ms 492 KB Output is correct
6 Correct 1 ms 512 KB Output is correct
7 Correct 1 ms 504 KB Output is correct
8 Correct 1 ms 492 KB Output is correct
9 Correct 1 ms 492 KB Output is correct
10 Correct 1 ms 492 KB Output is correct
11 Correct 1 ms 620 KB Output is correct
12 Correct 1 ms 620 KB Output is correct
13 Correct 1 ms 620 KB Output is correct
14 Correct 1 ms 620 KB Output is correct
15 Correct 1 ms 620 KB Output is correct
16 Correct 1 ms 620 KB Output is correct
17 Correct 1 ms 768 KB Output is correct
18 Correct 1 ms 620 KB Output is correct
19 Correct 1 ms 620 KB Output is correct
20 Correct 1 ms 620 KB Output is correct
21 Correct 5 ms 2156 KB Output is correct
22 Correct 5 ms 2156 KB Output is correct
23 Correct 5 ms 2156 KB Output is correct
24 Correct 5 ms 2156 KB Output is correct
25 Correct 5 ms 2156 KB Output is correct
26 Correct 5 ms 2156 KB Output is correct
27 Correct 5 ms 2156 KB Output is correct
28 Correct 5 ms 2156 KB Output is correct
29 Correct 5 ms 2156 KB Output is correct
30 Correct 5 ms 2156 KB Output is correct
31 Correct 44 ms 9324 KB Output is correct
32 Correct 44 ms 9452 KB Output is correct
33 Correct 45 ms 9452 KB Output is correct
34 Correct 44 ms 9452 KB Output is correct
35 Correct 44 ms 9452 KB Output is correct
36 Correct 45 ms 9452 KB Output is correct
37 Correct 45 ms 9580 KB Output is correct
38 Correct 44 ms 9472 KB Output is correct
39 Correct 44 ms 9464 KB Output is correct
40 Correct 44 ms 9452 KB Output is correct
41 Correct 1597 ms 134660 KB Output is correct
42 Correct 1590 ms 134636 KB Output is correct
43 Correct 1589 ms 134636 KB Output is correct
44 Correct 1711 ms 134532 KB Output is correct
45 Correct 1608 ms 134496 KB Output is correct
46 Correct 1590 ms 134692 KB Output is correct
47 Correct 1591 ms 134604 KB Output is correct
48 Correct 1591 ms 134720 KB Output is correct
49 Correct 1630 ms 134648 KB Output is correct
50 Correct 1606 ms 134636 KB Output is correct
51 Correct 1607 ms 134648 KB Output is correct
52 Correct 1587 ms 134684 KB Output is correct
53 Correct 1601 ms 134764 KB Output is correct
54 Correct 1665 ms 134604 KB Output is correct
55 Correct 1584 ms 134892 KB Output is correct