Create interleaving-string.cpp

Author: c650

interleaving-string.cpp

@@ -0,0 +1,32 @@
+class Solution {
+public:
+    bool isInterleave(string s1, string s2, string s3) {
+        if (s1.length() + s2.length() != s3.length()) {
+            return false;
+        }
+        
+        std::vector<std::vector<char>> memo(1 + s1.length(), std::vector<char>(1 + s2.length(), -1));
+        
+        std::function<bool(int,int)> go = [&](int a, int b) -> bool {
+            
+            int c = a + b;
+            if (c >= static_cast<int>(s3.length())) {
+                return true;
+            }
+            
+            char& ret = memo[a][b];
+            if (ret != -1) {
+                return ret;
+            }
+            
+            ret = false;
+            
+            ret |= (a < static_cast<int>(s1.length()) && s3[c] == s1[a] && go(a+1, b));
+            ret |= (b < static_cast<int>(s2.length()) && s3[c] == s2[b] && go(a, b+1));
+                       
+            return ret;
+        };
+        
+        return go(0,0);
+    }
+};