Submission #840760

#TimeUsernameProblemLanguageResultExecution timeMemory
840760PurpleCrayonSoccer Stadium (IOI23_soccer)C++17
64 / 100
4608 ms1599160 KiB
#include "soccer.h"
#include <bits/stdc++.h>
using namespace std;
 
#define ar array
#define sz(v) int(v.size())
typedef long long ll;
const int INF = 1e9+10;
const int M = 2e3+10;
 
struct Sparse {
    vector<vector<int>> sparse;
    Sparse() {}
    Sparse(vector<int>& v) {
        int n = v.size();
        sparse.push_back(v);
        for (int i = 1; (1 << i) <= n; i++) {
            sparse.push_back(vector<int>(n - (1 << i) + 1));
            for (int j = 0; j + (1 << i) <= n; j++) {
                sparse[i][j] = min(sparse[i-1][j], sparse[i-1][j + (1 << (i-1))]);
            }
        }
    }
 
    int qry(int l, int r) {
        assert(l <= r);
        int b = 31 - __builtin_clz(r - l + 1);
        // cerr << "> " << l << ' ' << r << ''
        return min(sparse[b][l], sparse[b][r - (1 << b) + 1]);
    }
} ones[M], twos[M];
 
int get_cost(int i, int l, int r) {
    return max(0, ones[i].qry(l, r) + twos[i].qry(l, r) - 1);
}

#include<bits/extc++.h>

struct splitmix64_hash {
	static uint64_t splitmix64(uint64_t x) {
		// http://xorshift.di.unimi.it/splitmix64.c
		x += 0x9e3779b97f4a7c15;
		x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
		x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
		return x ^ (x >> 31);
	}

	size_t operator()(uint64_t x) const {
		static const uint64_t FIXED_RANDOM = std::chrono::steady_clock::now().time_since_epoch().count();
		return splitmix64(x + FIXED_RANDOM);
	}
};

template <typename K, typename V, typename Hash = splitmix64_hash>
using hash_map = __gnu_pbds::gp_hash_table<K, V, Hash>;

template <typename K, typename Hash = splitmix64_hash>
using hash_set = hash_map<K, __gnu_pbds::null_type, Hash>;

 
int cnt_l[M][M], cnt_r[M][M];
int store_up[M][M], store_down[M][M];
vector<int> impl[M][M];
vector<int> impr[M][M];
vector<int> has[M][M];
hash_map<ll, int> dp;
 
ll h(int a, int b, int c) {
    return (long long) a * M * M + b * M + c;
}

int biggest_stadium(int N, std::vector<std::vector<int>> F) {
    for (int j = 0; j < N; j++) {
        int one = 0;
        for (int i = 0; i < N; i++) {
            one = F[i][j] ? 0 : one + 1;
            store_up[i][j] = one;
        }

        int two = 0;
        for (int i = N-1; i >= 0; i--) {
            two = F[i][j] ? 0 : two + 1;
            store_down[i][j] = two;
        }
    }

    for (int i = 0; i < N; i++) {
        vector<int> up(N), down(N);
        for (int j = 0; j < N; j++) {
            up[j] = store_up[i][j], down[j] = store_down[i][j];
            // while (i - up[j] >= 0 && !F[i - up[j]][j]) up[j]++;
            // while (i + down[j] < N && !F[i + down[j]][j]) down[j]++;
        }
 
        ones[i] = Sparse(up), twos[i] = Sparse(down);
    }
 
    auto add_imp = [&](int i, int l, int r) {
        has[l][r].push_back(i);
        cnt_l[i][l]++, cnt_r[i][r]++;
    };
 
    for (int i = 0; i < N; i++) {
        vector<int> blocks{-1};
        for (int j = 0; j < N; j++) if (F[i][j])
            blocks.push_back(j);
        
        blocks.push_back(N);
 
        for (int j = 1; j < sz(blocks); j++) if (blocks[j] > blocks[j-1] + 1) {
            int l = blocks[j-1]+1, r = blocks[j]-1;
            for (int k = l; k <= r; k++) {
                add_imp(i, k, r);
                if (k != r) add_imp(i, l, k);
            }
        }
    }
 
    for (int i = 0; i < N; i++) for (int j = 0; j < N; j++)
        impl[i][j].reserve(cnt_l[i][j]), impr[i][j].reserve(cnt_r[i][j]);

    for (int l = 0; l < N; l++) {
        for (int r = 0; r < N; r++) {
            for (int i : has[l][r]) {
                impl[i][l].push_back(r);
                impr[i][r].push_back(l);
            }
        }
    }
 
    auto upd = [&](int ni, int l, int r, int x, int cur_cost) {
        if (ni < 0 || ni >= N) return;
        int nl = upper_bound(impr[ni][r].begin(), impr[ni][r].end(), l) - impr[ni][r].begin();
        if (nl < sz(impr[ni][r])) {
            nl = impr[ni][r][nl];
            int& store = dp[h(ni, nl, r)];
            store = max(store, x + (get_cost(ni, nl, r) - cur_cost) * (r - nl + 1));
        }
 
        int nr = lower_bound(impl[ni][l].begin(), impl[ni][l].end(), r) - impl[ni][l].begin() - 1;
        if (nr >= 0) {
            nr = impl[ni][l][nr];
            int& store = dp[h(ni, l, nr)];
            store = max(store, x + (get_cost(ni, l, nr) - cur_cost) * (nr - l + 1));
        }
    };
 
    for (int l = 0; l < N; l++) {
        for (int r = N-1; r >= 0; r--) {
            for (int i : has[l][r]) {
                int cur_cost = get_cost(i, l, r);
                int store = dp[h(i, l, r)] = max(dp[h(i, l, r)], cur_cost * (r - l + 1));
                // cerr << l << ' ' << r << ' ' << i << ' ' << dp[{i, l, r}] << endl;
 
                int top = i - ones[i].qry(l, r);
                int bot = i + twos[i].qry(l, r);
                upd(i, l, r, store, cur_cost);
                upd(top, l, r, store, cur_cost);
                upd(bot, l, r, store, cur_cost);
            }
        }
    }
 
    int ans = 0;
    for (auto& [_, v] : dp) ans = max(ans, v);
    cerr << (double) clock() / CLOCKS_PER_SEC << endl;
    return ans;
}
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