Submission #791295

#	Time	Username	Problem	Language	Result	Execution time	Memory
791295		skittles1412	Rectangles (IOI19_rect)	C++17	0 / 100	114 ms	42488 KiB

rect

#include "bits/extc++.h"

using namespace std;

template <typename T, typename... U>
void dbgh(const T& t, const U&... u) {
    cerr << t;
    ((cerr << " | " << u), ...);
    cerr << endl;
}

#ifdef DEBUG
#define dbg(...)                                              \
    cerr << "L" << __LINE__ << " [" << #__VA_ARGS__ << "]: "; \
    dbgh(__VA_ARGS__)
#else
#define dbg(...)
#define cerr   \
    if (false) \
    cerr
#endif

using ll = long long;

#define endl "\n"
#define long int64_t
#define sz(x) int(std::size(x))

namespace s1 {

constexpr int DIRS[4][2] {{0, 1}, {0, -1}, {-1, 0}, {1, 0}};

int n, m;
vector<vector<char>> vis;
vector<vector<int>> arr;

bool ibs(int x, int y) {
    return 0 <= x && x < n && 0 <= y && y < m;
}

template <typename Cb>
void dfs(int x, int y, const Cb& cb) {
    if (!ibs(x, y) || vis[x][y] || arr[x][y]) {
        return;
    }
    cb(x, y);
    vis[x][y] = true;
    for (auto& [dx, dy] : DIRS) {
        dfs(x + dx, y + dy, cb);
    }
}

long solve(const vector<vector<int>>& _arr) {
    arr = _arr;
    n = sz(arr);
    m = sz(arr[0]);
    vis.resize(n, vector<char>(m));

    long ans = 0;

    auto c2 = [&](long n) -> long { return n * (n - 1) / 2; };

    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            if (vis[i][j] || arr[i][j]) {
                continue;
            }
            int mnx = 1e9, mxx = 0, mny = 1e9, mxy = 0, cnt = 0;
            dfs(i, j, [&](int x, int y) -> void {
                mnx = min(mnx, x);
                mxx = max(mxx, x);
                mny = min(mny, y);
                mxy = max(mxy, y);
                cnt++;
            });

            if (cnt == (mxx - mnx + 1) * (mxy - mny + 1) && mnx && mny &&
                mxx < n - 1 && mxy < m - 1) {
                ans += c2(mxx - mnx + 2) * c2(mxy - mny + 2);
            }
        }
    }

    return ans;
}

}  // namespace s1

ll count_rectangles(vector<vector<int>> arr) {
    int n = sz(arr), m = sz(arr[0]);

    {
        bool ok = true;
        for (auto& a : arr) {
            for (auto& b : a) {
                ok &= 0 <= b && b <= 1;
            }
        }
        if (ok) {
            return s1::solve(arr);
        }
    }
}

Compilation message (stderr)

rect.cpp: In function 'll count_rectangles(std::vector<std::vector<int> >)':
rect.cpp:90:9: warning: unused variable 'n' [-Wunused-variable]
   90 |     int n = sz(arr), m = sz(arr[0]);
      |         ^
rect.cpp:90:22: warning: unused variable 'm' [-Wunused-variable]
   90 |     int n = sz(arr), m = sz(arr[0]);
      |                      ^
rect.cpp:103:1: warning: control reaches end of non-void function [-Wreturn-type]
  103 | }
      | ^

• Subtask 1: 0 / 8
• Subtask 2: 0 / 7
• Subtask 3: 0 / 12
• Subtask 4: 0 / 22
• Subtask 5: 0 / 10
• Subtask 6: 0 / 13
• Subtask 7: 0 / 28