Submission #100577

#	Time	Username	Problem	Language	Result	Execution time	Memory
100577		alexpetrescu	Bomb (IZhO17_bomb)	C++14	100 / 100	541 ms	60280 KiB

bomb

#include <cstdio>
#include <algorithm>
 
//FILE *fin = fopen("a.in", "r"), *fout = fopen("a.out", "w");
#define fin stdin
#define fout stdout
 
#define MAXN 2500
 
int left[MAXN + 2][MAXN + 2], right[MAXN + 2][MAXN + 2];
int d[MAXN + 2];
char m[MAXN + 2][MAXN + 10];
int nrlin, nrcol;
 
inline void solve() {
    for (int i = 1; i <= nrlin; i++) {
        left[i][0] = 0;
        for (int j = 1; j <= nrcol; j++)
            if (m[i][j] == '1')
                left[i][j] = left[i][j - 1];
            else
                left[i][j] = j;
        right[i][nrcol + 1] = nrcol + 1;
        for (int j = nrcol; j > 0; j--)
            if (m[i][j] == '1')
                right[i][j] = right[i][j + 1];
            else
                right[i][j] = j;
 
        for (int j = 1; j <= nrcol; j++)
            if (m[i][j] == '1')
                d[1] = std::min(d[1], right[i][j] - left[i][j] - 1);
    }
 
    for (int j = 1; j <= nrcol; j++) {
        int st = 0, dr = nrcol + 1, cat = 0;
        for (int i = 1; i <= nrlin; i++) {
            if (m[i][j] == '1') {
                st = std::max(st, left[i][j]);
                dr = std::min(dr, right[i][j]);
                cat++;
                d[cat] = std::min(d[cat], dr - st - 1);
            } else {
                if (cat)
                    d[cat + 1] = 0;
                st = 0, dr = nrcol + 1;
                cat = 0;
            }
        }
        if (cat)
            d[cat + 1] = 0;
    }
}
 
int main() {
    fscanf(fin, "%d%d ", &nrlin, &nrcol);
 
    for (int i = 1; i <= nrlin; i++)
        fgets(m[i] + 1, MAXN + 5, fin), d[i] = nrcol;
 
    solve();
 
    for (int i = 1; i <= nrlin / 2; i++)
        for (int j = 1; j <= nrcol; j++)
            std::swap(m[i][j], m[nrlin - i + 1][j]);
 
    solve();
 
    for (int i = 2; i <= nrlin; i++)
        d[i] = std::min(d[i], d[i - 1]);
 
    int ans = d[1];
    for (int i = 2; i <= nrlin; i++)
        ans = std::max(ans, i * d[i]);
 
    fprintf(fout, "%d\n", ans);
 
    fclose(fin);
    fclose(fout);
    return 0;
}

Compilation message (stderr)

bomb.cpp: In function 'int main()':
bomb.cpp:56:11: warning: ignoring return value of 'int fscanf(FILE*, const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     fscanf(fin, "%d%d ", &nrlin, &nrcol);
     ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
bomb.cpp:59:39: warning: ignoring return value of 'char* fgets(char*, int, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
         fgets(m[i] + 1, MAXN + 5, fin), d[i] = nrcol;
         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~

• Subtask 1: 100 / 100