Create valid-word-abbreviation.cpp

Author: kamyu104

C++/valid-word-abbreviation.cpp

@@ -0,0 +1,30 @@
+// Time:  O(n)
+// Space: O(1)
+
+class Solution {
+public:
+    bool validWordAbbreviation(string word, string abbr) {
+        int i = 0, digit = 0;
+        for (const auto& c : abbr) {
+            if (isdigit(c)) {
+                if (digit == 0 && c == '0') {
+                    return false;
+                } 
+                digit *= 10;
+                digit += c - '0';
+            } else {
+                if (digit) {
+                    i += digit;
+                    digit = 0;
+                }
+                if (i >= word.length() || word[i++] != c) {
+                    return false;
+                }
+            }
+        }
+        if (digit) {
+            i += digit;
+        }
+        return i == word.length();
+    }
+};