leetcode

commit c151ea288ff0e52214030607a7a4c30c71193cd2
parent 36854e82f1b5605249853a1213464cab62ee70a6
Author: Jack Sangdahl <jack@pngu.org>
Date:   Tue, 16 Jun 2026 11:44:31 -0600

3612. process string with special operations 1

Diffstat:
A
process_str_special_op1.c
 | 
56
++++++++++++++++++++++++++++++++++++++++++++++++++++++++
A
process_str_special_op1.py
 | 
32
++++++++++++++++++++++++++++++++

2 files changed, 88 insertions(+), 0 deletions(-)
diff --git a/process_str_special_op1.c b/process_str_special_op1.c
@@ -0,0 +1,56 @@
+// 3612. Process String with Special Operations I
+#include "leetcode.h"
+
+/*
+ * you are given a string 's' containing lowercase english letters and the
+ * special characters '*', '#', and '%'. build a new string 'result' by
+ * processing 's' according to the following rules from left to right: if the
+ * letter is a lowercase english letter append it to 'result'. a '*' removes the
+ * last character from 'result'. a '#' duplicates the current 'result' and
+ * appends it to itself. a '%' reverses the current 'result'. return the
+ * resulting string.
+ */
+
+char *processStr(char *s) {
+  int cap = 1024, n = 0;
+  char *ans = (char *)malloc(cap * sizeof(char));
+  for (int i = 0; s[i] != '\0'; i++) {
+    char c = s[i];
+    if (c == '*') {
+      if (n > 0)
+        n--;
+    } else if (c == '#') {
+      while (n * 2 + 1 > cap) {
+        cap *= 2;
+        ans = (char *)realloc(ans, cap);
+      }
+      memcpy(ans + n, ans, n);
+      n *= 2;
+    } else if (c == '%') {
+      for (int l = 0, r = n - 1; l < r; l++, r--) {
+        char temp = ans[l];
+        ans[l] = ans[r];
+        ans[r] = temp;
+      }
+    } else {
+      if (n + 2 > cap) {
+        cap *= 2;
+        ans = (char *)realloc(ans, cap);
+      }
+      ans[n++] = c;
+    }
+  }
+  ans[n] = '\0';
+  return ans;
+}
+
+int main() {
+  char *s1 = "a#b%*", *r1 = "ba";
+  char *s2 = "z*#", *r2 = "";
+  char *ps1 = processStr(s1);
+  char *ps2 = processStr(s2);
+  printf("%s\n", ps1);
+  assert(!strcmp(ps1, r1));
+  printf("%s\n", ps2);
+  assert(!strcmp(ps2, r2));
+}
diff --git a/process_str_special_op1.py b/process_str_special_op1.py
@@ -0,0 +1,32 @@
+# 3612. Process String with Special Operations I
+
+"""
+you are given a string 's' containing lowercase english letters and the
+special characters '*', '#', and '%'. build a new string 'result' by
+processing 's' according to the following rules from left to right: if the
+letter is a lowercase english letter append it to 'result'. a '*' removes the
+last character from 'result'. a '#' duplicates the current 'result' and
+appends it to itself. a '%' reverses the current 'result'. return the
+resulting string.
+"""
+
+
+class Solution:
+    def processStr(self, s: str) -> str:
+        ans = ""
+        for c in s:
+            if c == "*":
+                ans = ans[:-1]
+            elif c == "#":
+                ans += ans
+            elif c == "%":
+                ans = ans[::-1]
+            else:
+                ans += c
+        return ans
+
+
+if __name__ == "__main__":
+    obj = Solution()
+    print(obj.processStr(s="a#b%*"))
+    print(obj.processStr(s="z*#"))