Submission #1064172

#	Time	Username	Problem	Language	Result	Execution time	Memory
1064172		AmirAli_H1	Soccer Stadium (IOI23_soccer)	C++17	77.50 / 100	398 ms	116852 KiB

soccer

// In the name of Allah

#include <bits/stdc++.h>
#include "soccer.h"
using namespace std;

typedef			long long				ll;
typedef			pair<int, int>			pii;
typedef			pair<ll, ll>			pll;

#define			F						first
#define			S						second
#define			endl					'\n'
#define			sep						' '
#define			pb						push_back
#define			Mp						make_pair
#define			all(x)					(x).begin(),(x).end()
#define			len(x)					((ll) (x).size())

const int maxn = 2000 + 4;
const int oo = 1e9 + 7;

int n;
int A[maxn][maxn];
vector<pii> ls;
int val1[maxn][maxn], val2[maxn][maxn];
pii val[maxn]; int dp[maxn][maxn];
pii valx[maxn][maxn];

bool cmp(pii i, pii j) {
	return ((i.S - i.F) > (j.S - j.F));
}

bool is_ok() {
	ls.clear();
	for (int i = 0; i < n; i++) {
		int x = 0;
		for (int j = 0; j < n; j++) {
			if (A[i][j] != A[i][x]) {
				if (A[i][x] == 0) ls.pb(Mp(x, j - 1));
				x = j;
			}
		}
		if (A[i][x] == 0) ls.pb(Mp(x, n - 1));
	}
	sort(all(ls), cmp);
	
	for (int i = 1; i < len(ls); i++) {
		if (ls[i].F < ls[i - 1].F || ls[i].S > ls[i - 1].S) return 0;
	}
	return 1;
}

int check() {
	int num = 0; 
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) num += (A[i][j] == 0);
	}
	
	bool ok = 1;
	ok &= is_ok();
	for (int i = 0; i < n; i++) {
		for (int j = i; j < n; j++) swap(A[i][j], A[j][i]);
	}
	ok &= is_ok();
	for (int i = 0; i < n; i++) {
		for (int j = i; j < n; j++) swap(A[i][j], A[j][i]);
	}
	if (ok) return num;
	else return 0;
}

int get_val(int y) {
	for (int x = 0; x < n; x++) {
		if (A[x][y] == 1) val[x] = Mp(n, -1);
		else val[x] = Mp(val1[x][y], val2[x][y]);
	}
	
	int res = 0;
	for (int ln = 1; ln <= n; ln++) {
		for (int l = 0, r = ln - 1; r < n; l++, r++) {
			if (ln == 1) {
				valx[l][r] = val[l];
				if (valx[l][r].F > valx[l][r].S) dp[l][r] = -oo;
				else dp[l][r] = (valx[l][r].S - valx[l][r].F + 1);
			}
			else {
				valx[l][r] = val[l];
				valx[l][r].F = max(valx[l][r].F, valx[l + 1][r].F);
				valx[l][r].S = min(valx[l][r].S, valx[l + 1][r].S);
				if (valx[l][r].F > valx[l][r].S) dp[l][r] = -oo;
				else dp[l][r] = (valx[l][r].S - valx[l][r].F + 1) + max(dp[l + 1][r], dp[l][r - 1]);
			}
			dp[l][r] = max(dp[l][r], -oo);
			res = max(res, dp[l][r]);
		}
	}
	
	return res;
}

int solve() {
	int mx = 0;
	for (int j = 0; j < n; j++) {
		mx = max(mx, get_val(j));
	}
	return mx;
}

int biggest_stadium(int N, vector<vector<int>> F) {
	n = N;
	for (int i = 0; i < n; i++) {
		for (int j = 0; j < n; j++) {
			A[i][j] = F[i][j];
			if (A[i][j] == 1) ls.pb(Mp(i, j));
		}
	}
	
	if (len(ls) == 0) return (n * n);
	else if (len(ls) == 1) {
		int i = ls.back().F, j = ls.back().S;
		return (n * n) - (min(i + 1, n - i) * min(j + 1, n - j));
	}
	
	for (int i = 0; i < n; i++) {
		int x = 0;
		for (int j = 0; j < n; j++) {
			if (A[i][j] != A[i][x]) x = j;
			val1[i][j] = x;
		}
		x = n - 1;
		for (int j = n - 1; j >= 0; j--) {
			if (A[i][j] != A[i][x]) x = j;
			val2[i][j] = x;
		}
	}
	
	if (n <= 500) return solve();
	else return check();
}

• Subtask 0: 0 / 0
• Subtask 1: 6 / 6
• Subtask 2: 8 / 8
• Subtask 3: 22 / 22
• Subtask 4: 18 / 18
• Subtask 5: 16 / 16
• Subtask 6: 7.5 / 30