Create check-if-string-is-a-prefix-of-array.cpp

Author: kamyu104

C++/check-if-string-is-a-prefix-of-array.cpp

@@ -0,0 +1,40 @@
+// Time:  O(n)
+// Space: O(1)
+
+class Solution {
+public:
+    bool isPrefixString(string s, vector<string>& words) {
+        int i = 0, j = 0;
+        for (const auto& c : s) {
+            if (i == size(words) || words[i][j] != c) {
+                return false;
+            }
+            if (++j == size(words[i])) {
+                ++i;
+                j = 0;
+            }
+        }
+        return j == 0;
+    }
+};
+
+// Time:  O(n)
+// Space: O(1)
+class Solution2 {
+public:
+    bool isPrefixString(string s, vector<string>& words) {
+        int i = 0;
+        for (const auto& word : words) {
+            for (const auto& c : word) {
+                if (i == size(s) || s[i] != c) {
+                    return false;
+                }
+                ++i;
+            }
+            if (i == size(s)) {
+                return true;
+            }
+        }
+        return false;
+    }
+};