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-rw-r--r--res_str_adj_remove.c42
1 files changed, 42 insertions, 0 deletions
diff --git a/res_str_adj_remove.c b/res_str_adj_remove.c
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+// 3561. Resulting String After Adjacent Removals
+#include "leetcode.h"
+
+/*
+ * you are given a string 's' consisting of lowercase english letters. you must
+ * repeatedly perform the following operation while the string 's' has at least
+ * two consecutive characters: remove the leftmost pair of adjacent characters
+ * in the string that are consecutive in the alphabet, in either order, and
+ * shift the remaining characters to the left to fill the gap. return the
+ * resulting string after no more operations can be performed. note: consider
+ * the alphabet as circular, thus 'a' and 'z' are consecutive.
+ */
+
+bool helper(char a, char b) {
+ int c = fabs(a - b);
+ return c == 1 || c == 25;
+}
+
+char *resultingString(char *s) {
+ int n = strlen(s), top = -1;
+ char *ans = (char *)malloc((n + 1) * sizeof(char));
+ for (int i = 0; i < n; i++) {
+ if (top >= 0 && helper(ans[top], s[i]))
+ top--;
+ else
+ ans[++top] = s[i];
+ }
+ ans[top + 1] = '\0';
+ return ans;
+}
+
+int main() {
+ char *s1 = "abc", *rs1 = resultingString(s1);
+ char *s2 = "adcb", *rs2 = resultingString(s2);
+ char *s3 = "zadb", *rs3 = resultingString(s3);
+ printf("%s\n", rs1); // expect: c
+ printf("%s\n", rs2); // expect: null
+ printf("%s\n", rs3); // expect: db
+ free(rs1);
+ free(rs2);
+ free(rs3);
+}