1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
|
// 1349. Maximum Students Taking Exam
#include "leetcode.h"
/*
* given an 'm x n' matrix 'seats' that represent seats distributions in a
* classroom. if a seat is broken, it is denoted by '#' character otherwise it
* is denoted by a '.' character. students can see theanswers of those sitting
* next to the left, right, upper left, and upper right, but cannot see the
* answers of the student sitting directly in front of or behind them. return
* the maximum number of students that can take the exam together without any
* cheating being possible. students must be placed in seats in good condition.
*/
int maxStudents(char **seats, int seatsSize, int *seatsColSize) {
int n = seatsSize, m = *seatsColSize, ans = 0, dp[9][(1 << 8) + 2], avail[9];
memset(dp, -1, sizeof(dp));
for (int i = 1; i <= n; i++)
for (int j = 0; j < m; j++)
if (seats[i - 1][j] == '.')
avail[i] |= (1 << j);
for (int mask = 0; mask < (1 << m); mask++)
dp[0][mask] = 0;
for (int i = 1; i <= n; i++)
for (int pre = 0; pre < (1 << m); pre++) {
if (dp[i - 1][pre] == -1)
continue;
for (int mask = 0; mask < (1 << m); mask++) {
if ((mask & avail[i]) != mask)
continue;
if (mask & (mask >> 1))
continue;
if (mask & (pre << 1) || mask & (pre >> 1))
continue;
dp[i][mask] =
fmax(dp[i][mask], dp[i - 1][pre] + __builtin_popcount(mask));
}
}
for (int mask = 0; mask < (1 << m); mask++)
ans = fmax(ans, dp[n][mask]);
return ans;
}
int main() {
char *s1[] = {"#", ".", "#", "#", ".", "#", ".", "#", "#",
"#", "#", ".", "#", ".", "#", "#", ".", "#"};
int ss1 = 3, scs1 = 6;
char *s2[] = {".", "#", "#", "#", "#", ".", "#", "#", ".", "#"};
int ss2 = 5, scs2 = 2;
char *s3[] = {"#", ".", ".", ".", "#", ".", "#", ".", "#", ".", ".", ".", "#",
".", ".", ".", "#", ".", "#", ".", "#", ".", ".", ".", "#"};
int ss3 = 5, scs3 = 5;
printf("%d\n", maxStudents((char **)s1, ss1, &scs1)); // expect: 4
printf("%d\n", maxStudents((char **)s2, ss2, &scs2)); // expect: 3
printf("%d\n", maxStudents((char **)s3, ss3, &scs3)); // expect: 10
}
|