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-rw-r--r--split_string_max_unique_substr.c70
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diff --git a/split_string_max_unique_substr.c b/split_string_max_unique_substr.c
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+// 1593. Split a String Into the Max Number of Unique Substrings
+#include "leetcode.h"
+
+/*
+ * given a string 's', return the maximum number of unique substrings that the
+ * given string can be split into. you can split string 's' into any list of
+ * non-empty substrings, where the concatenation of the substrings forms the
+ * origin string. however, you must split the substrings such that all of them
+ * are unique. a substring is a contiguous sequence of characters within a
+ * string.
+ */
+
+struct map {
+ int len;
+ char s[16];
+};
+
+bool find(struct map *m, int idx, char *tmp, int tmp_len) {
+ if (idx == -1)
+ return false;
+ for (int i = 0; i <= idx; i++)
+ if (m[i].len == tmp_len)
+ if (!strncmp(m[i].s, tmp, tmp_len))
+ return true;
+ return false;
+}
+
+bool is_valid(char *s, int s_len, int split, int *active_bits) {
+ struct map m[s_len];
+ int idx = -1, tmp_len = 1;
+ char tmp[s_len];
+ memcpy(&tmp[0], &s[0], 1);
+ for (int i = 0; i < s_len - 1; i++) {
+ if ((split >> i) & 1) {
+ if (find(m, idx, tmp, tmp_len))
+ return false;
+ idx++;
+ memcpy(&(m[idx].s), &tmp[0], tmp_len);
+ m[idx].s[tmp_len] = '\0';
+ m[idx].len = tmp_len;
+ (*active_bits)++;
+ tmp_len = 0;
+ tmp[tmp_len++] = s[i + 1];
+ } else
+ tmp[tmp_len++] = s[i + 1];
+ }
+ if (tmp_len && find(m, idx, tmp, tmp_len))
+ return false;
+ return true;
+}
+
+int maxUniqueSplit(char *s) {
+ int n = strlen(s);
+ if (n == 1)
+ return 1;
+ int max_size = pow(2, n - 1), max_split = 0;
+ for (int i = 0; i < max_size; i++) {
+ int m = 0;
+ if (is_valid(s, n, i, &m))
+ max_split = fmax(max_split, m);
+ }
+ return max_split + 1;
+}
+
+int main() {
+ char *s1 = "ababccc", *s2 = "aba", *s3 = "aa";
+ printf("%d\n", maxUniqueSplit(s1)); // expect: 5
+ printf("%d\n", maxUniqueSplit(s2)); // expect: 2
+ printf("%d\n", maxUniqueSplit(s3)); // expect: 1
+}