oj.uz

Submission #945074

# Submission time Handle Problem Language Result Execution time Memory
945074 2024-03-13T11:26:46 Z atom Bomb (IZhO17_bomb) C++17
80 / 100
 1000 ms 131072 KB 
#include "bits/stdc++.h"
// @JASPER'S BOILERPLATE
using namespace std;
using ll = long long;
 
#ifdef JASPER
#include "debug.h"
#else
#define debug(...) 166
#endif
 
signed main() {
    cin.tie(0) -> sync_with_stdio(0);
    #ifdef JASPER
        freopen("in1", "r", stdin);
    #endif
 
    int n, m;
    cin >> n >> m;
    vector <vector <int>> a(n + 5, vector <int> (m + 5, 0));
    for (int i = 1; i <= n; ++i) {
        for (int j = 1; j <= m; ++j) {
            char x; cin >> x;
            a[i][j] = x - '0';
        }
    }
 
    // for (int i = 1; i <= n; ++i) 
    //     for (int j = 1; j <= m; ++j)
    //         cout << a[i][j] << " \n"[j == m]; 
 
    //sub1: shortest consecutive 1ss
    if (n == 1 || m == 1) {
        if (n == 1) {
            int ans = 1e9;
            for (int i = 1; i <= m; ++i) {
                if (a[1][i] == 0) continue;
                int cur = 0;
                while (i <= m && a[1][i]) { 
                    ++cur;
                    ++i;
                }
                ans = min(ans, cur);
            }
            cout << ans << "\n";
            return 0;
        }
        if (m == 1) {
            int ans = 1e9;
            for (int i = 1; i <= n; ++i) {
                if (a[i][1] == 0) continue;
                int cur = 0;
                while (i <= n && a[i][1]) { 
                    ++cur;
                    ++i;
                }
                ans = min(ans, cur);
            }
            cout << ans << "\n";
            return 0;
        }
    }
 
    // sub3
    // if (n <= 450 && m <= 450) {
    //     vector <vector <int>> prf(n + 5, vector <int> (m + 5, 0));
    //     int earth = 0;
    //     for (int i = 1; i <= n; ++i) {
    //         for (int j = 1; j <= m; ++j) {
    //             earth += (a[i][j] == 0);
    //             prf[i][j] = prf[i][j - 1] + prf[i - 1][j] - prf[i - 1][j - 1] + a[i][j];
    //         }
    //     }
 
    //     int ans = 0;
    //     for (int x = 1; x <= n; ++x) {
    //         for (int y = 1; y <= m; ++y) {
    //             if (x * y <= ans) continue;
 
    //             // prf(l)++, prf(r + 1)--;
    //             vector <vector <int>> dmg(n + 2, vector <int> (m + 2, 0));
 
    //             for (int i = 1; i + x - 1 <= n; ++i) {
    //                 for (int j = 1; j + y - 1 <= m; ++j) {
    //                     int I = i + x - 1, J = j + y - 1;
    //                     if (prf[I][J] + prf[i - 1][j - 1] - prf[I][j - 1] - prf[i - 1][J] == x * y) {
    //                         dmg[i][j] += 1;
    //                         dmg[I + 1][j] -= 1;
    //                         dmg[i][J + 1] -= 1;
    //                         dmg[I + 1][J + 1] += 1;
    //                     }
    //                 }
    //             }
 
    //             for (int i = 1; i <= n; ++i)
    //                 for (int j = 1; j <= m; ++j)
    //                     dmg[i][j] += dmg[i - 1][j] + dmg[i][j - 1] - dmg[i - 1][j - 1];

    //             bool valid = 1;
    //             for (int i = 1; i <= n; ++i) {
    //                 for (int j = 1; j <= m; ++j) {
    //                     if (a[i][j] && !dmg[i][j])
    //                         valid = 0;
    //                 }
    //             }
    //             if (valid) ans = max(ans, x * y);
    //         }
    //     }
 
    //     cout << ans << "\n";
    //     return 0;
    // }
    


    // two pointer to optimize
    vector <vector <int>> lt(n + 5, vector <int> (m + 5, 0)), rt(n + 5, vector <int> (m + 5, 0));
    vector <int> w(n + 5, 1e9); // ans(i) : W when H = i
    int min_h = 1e9;// minimum vertical strip of 1s;

    for (int _i = 0; _i <= 1; _i++) {
        for (int i = 1; i <= n; ++i) {
            for (int j = 1; j <= m; ++j)
                a[i][j]? lt[i][j] = (lt[i][j - 1] + 1) : 0;

            for (int j = m; j >= 1; --j)
                a[i][j]? rt[i][j] = (rt[i][j + 1] + 1) : 0;

            for (int j = 1; j <= m; ++j)
                if (a[i][j]) w[1] = min(w[1], rt[i][j] + lt[i][j] - (lt[i][j] && rt[i][j]));
        }
        // find feasible height
        for (int j = 1; j <= m; ++j) {
            int k = 0; // length of consecutive 1s of current column
            int l = 1e9, r = 1e9;
            for (int i = 1; i <= n; ++i) {
                if (a[i][j]) {
                    ++k;
                    l = min(l, lt[i][j]);
                    r = min(r, rt[i][j]);
                    w[k] = min(w[k], r + l - (lt[i][j] && rt[i][j]));
                }
                else {
                    if (k) min_h = min(min_h, k);
                    l = r = 1e9;
                    k = 0;
                }
            }
        }

        for (int i = 1; i <= n / 2; ++i) {
            for (int j = 1; j <= m; ++j)
                swap(a[i][j], a[n - i + 1][j]);
        }

    }

    int ans = 0;
    for (int h = 1; h <= min_h; ++h) {
        w[h + 1] = min(w[h + 1], w[h]); // width is bounded by the minimum horizontal strip
        ans = max(ans, w[h] * h);
    }

    cout << ans << "\n";
}

Subtask #1
80.0 / 100.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 348 KB Output is correct
5 Correct 0 ms 348 KB Output is correct
6 Correct 0 ms 348 KB Output is correct
7 Correct 0 ms 348 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Incorrect 0 ms 348 KB Output isn't correct
10 Correct 0 ms 344 KB Output is correct
11 Correct 0 ms 348 KB Output is correct
12 Correct 0 ms 348 KB Output is correct
13 Correct 1 ms 348 KB Output is correct
14 Correct 0 ms 348 KB Output is correct
15 Correct 0 ms 348 KB Output is correct
16 Correct 0 ms 348 KB Output is correct
17 Correct 0 ms 348 KB Output is correct
18 Correct 1 ms 348 KB Output is correct
19 Correct 0 ms 348 KB Output is correct
20 Correct 1 ms 344 KB Output is correct
21 Correct 0 ms 348 KB Output is correct
22 Correct 0 ms 348 KB Output is correct
23 Correct 1 ms 344 KB Output is correct
24 Incorrect 0 ms 348 KB Output isn't correct
25 Correct 1 ms 344 KB Output is correct
26 Correct 1 ms 348 KB Output is correct
27 Correct 3 ms 1372 KB Output is correct
28 Correct 3 ms 1628 KB Output is correct
29 Correct 5 ms 1880 KB Output is correct
30 Incorrect 6 ms 2764 KB Output isn't correct
31 Incorrect 4 ms 2136 KB Output isn't correct
32 Incorrect 4 ms 2140 KB Output isn't correct
33 Correct 6 ms 2908 KB Output is correct
34 Correct 2 ms 1372 KB Output is correct
35 Correct 5 ms 2908 KB Output is correct
36 Correct 8 ms 2952 KB Output is correct
37 Incorrect 0 ms 344 KB Output isn't correct
38 Execution timed out 2714 ms 131072 KB Time limit exceeded
39 Incorrect 0 ms 348 KB Output isn't correct
40 Correct 36 ms 9716 KB Output is correct
41 Correct 0 ms 348 KB Output is correct
42 Correct 1 ms 348 KB Output is correct
43 Correct 405 ms 74380 KB Output is correct
44 Correct 7 ms 2908 KB Output is correct
45 Incorrect 398 ms 74388 KB Output isn't correct
46 Correct 362 ms 74380 KB Output is correct
47 Incorrect 413 ms 74324 KB Output isn't correct
48 Correct 389 ms 74388 KB Output is correct
49 Correct 502 ms 74496 KB Output is correct
50 Correct 378 ms 74252 KB Output is correct
51 Correct 388 ms 74388 KB Output is correct
52 Correct 371 ms 74240 KB Output is correct
53 Correct 373 ms 74496 KB Output is correct
54 Correct 293 ms 74320 KB Output is correct
55 Correct 292 ms 74580 KB Output is correct
56 Execution timed out 2667 ms 131072 KB Time limit exceeded
57 Correct 288 ms 74384 KB Output is correct
58 Correct 289 ms 74324 KB Output is correct
59 Correct 297 ms 74508 KB Output is correct
60 Correct 360 ms 74316 KB Output is correct
61 Correct 500 ms 74384 KB Output is correct
62 Correct 508 ms 74324 KB Output is correct
63 Correct 499 ms 74576 KB Output is correct
64 Correct 300 ms 74516 KB Output is correct
65 Correct 362 ms 74320 KB Output is correct
66 Correct 374 ms 74576 KB Output is correct
67 Correct 385 ms 74236 KB Output is correct
68 Correct 413 ms 74380 KB Output is correct
69 Correct 275 ms 74392 KB Output is correct
70 Correct 131 ms 47700 KB Output is correct
71 Incorrect 265 ms 74380 KB Output isn't correct
72 Correct 277 ms 74320 KB Output is correct
73 Incorrect 295 ms 74492 KB Output isn't correct
74 Incorrect 278 ms 74244 KB Output isn't correct
75 Incorrect 298 ms 74324 KB Output isn't correct
76 Correct 294 ms 74324 KB Output is correct
77 Correct 294 ms 74324 KB Output is correct
78 Correct 301 ms 74472 KB Output is correct
79 Correct 190 ms 74384 KB Output is correct
80 Correct 205 ms 74384 KB Output is correct
81 Correct 208 ms 74320 KB Output is correct
82 Correct 297 ms 74320 KB Output is correct
83 Incorrect 299 ms 74384 KB Output isn't correct
84 Correct 192 ms 74240 KB Output is correct
85 Correct 290 ms 74388 KB Output is correct
86 Correct 462 ms 74388 KB Output is correct
87 Correct 289 ms 74576 KB Output is correct
88 Incorrect 299 ms 74236 KB Output isn't correct
89 Correct 344 ms 74580 KB Output is correct
90 Incorrect 174 ms 47700 KB Output isn't correct
91 Correct 346 ms 74320 KB Output is correct
92 Correct 345 ms 74392 KB Output is correct
93 Correct 447 ms 74324 KB Output is correct
94 Correct 348 ms 74324 KB Output is correct
95 Incorrect 307 ms 74320 KB Output isn't correct
96 Incorrect 307 ms 74580 KB Output isn't correct
97 Correct 484 ms 74388 KB Output is correct
98 Correct 324 ms 74236 KB Output is correct
99 Correct 374 ms 74380 KB Output is correct
100 Correct 455 ms 74324 KB Output is correct