Submission #529544

#	Time	Username	Problem	Language	Result	Execution time	Memory
529544		abc864197532	Group Photo (JOI21_ho_t3)	C++17	100 / 100	706 ms	196564 KiB

Main

#include <bits/stdc++.h>
using namespace std;
#define lli long long int
#define pb push_back
#define eb emplace_back
#define pii pair<int,int>
#define X first
#define Y second
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
void abc() {cout << endl;}
template <typename T, typename ...U> void abc(T i, U ...j) {
	cout << i << ' ', abc(j...);
}
template <typename T> void printv(T l, T r) {
	for (; l != r; ++l) cout << *l << " \n"[l + 1 == r];
}
#ifdef Doludu
#define test(x...) abc("[" + string(#x) + "]", x)
#define owo freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout)
#else
#define test(x...) void(0)
#define owo ios::sync_with_stdio(false), cin.tie(0)
#endif
const int N = 200000;

int main () {
	owo;
	int n;
	cin >> n;
	vector <int> p(n);
	for (int i = 0; i < n; ++i)
		cin >> p[i], --p[i];
	vector <int> dp(n + 1, 1 << 30);
	vector <vector <int>> cost(n + 1, vector <int> (n + 1, 0));
	vector <vector <int>> inversion(n + 1, vector <int> (n + 1, 0));
	for (int i = 0; i < n; ++i) {
		for (int j = i + 1; j < n; ++j) {
			if (p[i] > p[j])
				inversion[p[j]][p[i] + 1]++;
		}
	}
	for (int i = 0; i < n; ++i) {
		for (int j = 0; j < n; ++j) {
			inversion[i][j + 1] += inversion[i][j];
		}
	}
	vector <int> q(n);
	for (int r = 1; r <= n; ++r) {
		int t = 0;
		for (int i = 0; i < n; ++i) if (p[i] < r)
			q[p[i]] = t++;
		for (int l = r - 1; ~l; --l) {
			cost[l][r] = cost[l + 1][r] + r - q[l] - 1 - inversion[l][r];
		}
	}
	dp[0] = 0;
	for (int i = 1; i <= n; ++i) {
		for (int j = 0; j < i; ++j) {
			// max at postion j
			dp[i] = min(dp[i], dp[j] + cost[j][i]);
		}
	}
	cout << dp[n] << endl;
}

• Subtask 1: 5 / 5
• Subtask 2: 7 / 7
• Subtask 3: 32 / 32
• Subtask 4: 20 / 20
• Subtask 5: 36 / 36