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-rw-r--r--reorganise_string.c52
1 files changed, 52 insertions, 0 deletions
diff --git a/reorganise_string.c b/reorganise_string.c
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--- /dev/null
+++ b/reorganise_string.c
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+// 767. Reorganize String
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+/*
+ * given a string 's', rearrange the characters of 's' so that any two adjacent
+ * characters are not the same. return any possible arrangement of 's', or
+ * return "" if not possible.
+ */
+
+char find_max(int hist[26], char c) {
+ int max = 0;
+ char out = '\0';
+ for (int i = 0; i < 26; i++)
+ if (i + 'a' != c && hist[i] > max) {
+ max = hist[i];
+ out = i + 'a';
+ }
+ return out;
+}
+
+char *reorganizeString(char *s) {
+ int hist[26] = {0};
+ if (!strlen(s))
+ return s;
+ for (int i = 0; i < strlen(s); i++)
+ hist[s[i] - 'a']++;
+ char max = find_max(hist, '\0'), last;
+ int idx = 0;
+ char *out = (char *)malloc(sizeof(char) * (strlen(s) + 1));
+ while (max != '\0') {
+ out[idx++] = max;
+ last = max;
+ hist[last - 'a']--;
+ max = find_max(hist, last);
+ }
+ if (idx != strlen(s)) {
+ free(out);
+ return "";
+ }
+ out[idx] = '\0';
+ strcpy(s, out);
+ free(out);
+ return s;
+}
+
+int main() {
+ char s1[] = {"aab"}, s2[] = {"aaab"};
+ printf("%s\n", reorganizeString(s1)); // expect: aba
+ printf("%s\n", reorganizeString(s2)); // expect:
+}