diff --git a/0058_length_of_last_word/word_length.c b/0058_length_of_last_word/word_length.c
index b18cec9..bad2085 100644
--- a/0058_length_of_last_word/word_length.c
+++ b/0058_length_of_last_word/word_length.c
@@ -1,18 +1,20 @@
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 
 int lengthOfLastWord(char *s)
 {
-    int len = 0;
-    while (*s != '\0') {
-        if (s[-1] == ' ' && s[0] != ' ') {
-            len = 1;
-        } else if (*s != ' ') {
-            len++;
-        }
-        s++;
+    int word_len = 0;
+    int len = strlen(s);
+
+    while (len > 0 && s[--len] == ' ') {}
+
+    while (len >= 0 && s[len] != ' ') {
+        word_len++;
+        len--;
     }
-    return len;
+
+    return word_len;
 }
 
 int main(int argc, char **argv)
diff --git a/0070_climbing_stairs/climb_stairs.c b/0070_climbing_stairs/climb_stairs.c
index 3ecc50c..e1e05ea 100644
--- a/0070_climbing_stairs/climb_stairs.c
+++ b/0070_climbing_stairs/climb_stairs.c
@@ -4,28 +4,25 @@
 
 static int dfs(int n, int *count)
 {
-    if (n == 0) {
-        return 0;
+    if (n == 1) {
+        return 1;
+    } else if (n == 2) {
+        return 2;
     } else if (count[n] > 0) {
         return count[n];
     } else {
-        if (n >= 1) {
-            count[n] += dfs(n - 1, count);
-        }
-        if (n >= 2) {
-            count[n] += dfs(n - 2, count);
-        }
+        count[n] += dfs(n - 1, count);
+        count[n] += dfs(n - 2, count);
         return count[n];
     }
 }
 
 static int climbStairs(int n)
 {
-#if 0
+#if 1
+    if (n < 1) return 0;
     int *count = malloc((n + 1) * sizeof(int));
     memset(count, 0, (n + 1) * sizeof(int));
-    count[1] = 1;
-    count[2] = 2;
     return dfs(n, count);
 #else
     int i, a = 1, b = 2, c;
diff --git a/0083_remove_duplicates_from_sorted_list/rm_dup.c b/0083_remove_duplicates_from_sorted_list/rm_dup.c
index f5b7c7f..e8d7d4a 100644
--- a/0083_remove_duplicates_from_sorted_list/rm_dup.c
+++ b/0083_remove_duplicates_from_sorted_list/rm_dup.c
@@ -1,3 +1,4 @@
+#include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
 
@@ -9,16 +10,19 @@ struct ListNode {
 
 struct ListNode* deleteDuplicates(struct ListNode* head)
 {
-    struct ListNode *p, *q;
-    p = q = head;
-    while (p != NULL) {
-        while (q != NULL && q->val == p->val) {
-            q = q->next;
+    struct ListNode dummy;
+    struct ListNode *prev = &dummy;
+    dummy.val = INT_MIN;
+
+    while (head != NULL) {
+        if (prev->val != head->val) {
+            prev->next = head;
+            prev = head;
         }
-        p->next = q;
-        p = q;
+        head = head->next;
     }
-    return head;
+    prev->next = head;
+    return dummy.next;
 }
 
 int main(int argc, char **argv)