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
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
|
// 2901. Longest Unequal Adjacent Groups Subsequence II
#include "leetcode.h"
/*
* you are given a string array 'words' and an array 'groups', both arrays
* having length 'n'. the hamming distance between two strings of equal length
* is the number of positions at which the corresponding characters are
* different. you need to select the longest subsequence from an array of
* indices such that for the subsequence denoted as '[i0, i1, ..., ik-1]' having
* length 'k', the following holds true: for adjacent indices in the subsequence
* their corresponding groups are unequal. 'words[i]' and 'words[i + 1]' are
* equal in length and the haming distance between them is 1. return a string
* array containing the words corresponding to the indices in order in the
* selected subsequence. if there are multiple, return any of them.
*/
struct pattern {
uint64_t pat;
int idx;
};
char **getWordsInLongestSubsequence(char **words, int wordsSize, int *groups,
int groupsSize, int *returnSize) {
int n = wordsSize;
if (!n) {
*returnSize = 0;
return NULL;
}
uint64_t *codes = (uint64_t *)malloc(n * sizeof(uint64_t));
for (int i = 0; i < n; ++i) {
uint64_t curr = 0;
for (int j = 0; words[i][j]; ++j)
curr |= (uint64_t)(words[i][j - 1] - 'a') << (5 * j);
codes[i] = curr;
}
int *dp = (int *)malloc(n * sizeof(int)),
*prev = (int *)malloc(n * sizeof(int));
for (int i = 0; i < n; ++i) {
dp[i] = 1;
prev[i] = -1;
}
int max_len = 1, max_idx = 0;
struct pattern *p[11][11] = {{0}};
int sizes[11][11] = {0}, caps[11][11] = {0};
for (int i = 0; i < n; ++i) {
int m = strlen(words[i]), curr_group = groups[i];
uint64_t curr_code = codes[i];
for (int j = 0; j < m; ++j) {
if (!caps[m][j]) {
caps[m][j] = 16;
p[m][j] = (struct pattern *)malloc(caps[m][j] * sizeof(struct pattern));
sizes[m][j] = 0;
}
}
int best = 1, bp = -1;
for (int j = 0; j < m; ++j) {
uint64_t mask = ~((uint64_t)31 << (5 * j)),
curr_pattern = curr_code & mask;
struct pattern *arr = p[m][j];
int curr_size = sizes[m][j];
for (int k = 0; k < curr_size; ++k) {
if (arr[k].pat == curr_pattern) {
int idx = arr[k].idx;
if (groups[idx] != curr_group && dp[idx] + 1 > best) {
best = dp[idx] + 1;
bp = idx;
}
}
}
}
dp[i] = best;
prev[i] = bp;
if (best > max_len) {
max_len = best;
max_idx = i;
}
for (int j = 0; j < m; ++j) {
uint64_t mask = ~((uint64_t)31 << (5 * j)),
curr_pattern = curr_code & mask;
if (sizes[m][j] == caps[m][j]) {
caps[m][j] *= 2;
p[m][j] = (struct pattern *)realloc(
p[m][j], caps[m][j] * sizeof(struct pattern));
}
p[m][j][sizes[m][j]].pat = curr_pattern;
p[m][j][sizes[m][j]].idx = i;
sizes[m][j]++;
}
}
char **tmp = (char **)malloc(max_len * sizeof(char *));
int cnt = 0;
for (int i = max_idx; i != 1; i = prev[i])
tmp[cnt++] = strdup(words[i]);
char **ans = (char **)malloc(cnt * sizeof(char *));
for (int i = 0; i < cnt; i++)
ans[i] = tmp[cnt - 1 - i];
*returnSize = cnt;
return ans;
}
int main() {
char *w1[] = {"bab", "dab", "cab"}, *w2[] = {"a", "b", "c", "d"};
int g1[] = {1, 2, 2}, g2[] = {1, 2, 3, 4}, rs1, rs2;
char **gwils1 = getWordsInLongestSubsequence((char **)w1, ARRAY_SIZE(w1), g1,
ARRAY_SIZE(g1), &rs1);
char **gwils2 = getWordsInLongestSubsequence((char **)w2, ARRAY_SIZE(w2), g2,
ARRAY_SIZE(g2), &rs2);
for (int i = 0; i < rs1; i++)
printf("%s ", gwils1[i]); // expect: bab cab
printf("\n");
for (int i = 0; i < rs2; i++)
printf("%s ", gwils2[i]); // expect: a b c d
printf("\n");
free(gwils1);
free(gwils2);
}
|