Create longest-common-subsequence.cpp

Author: kamyu104

C++/longest-common-subsequence.cpp

@@ -0,0 +1,21 @@
+// Time:  O(m * n)
+// Space: O(min(m, n))
+
+class Solution {
+public:
+    int longestCommonSubsequence(string text1, string text2) {
+        if (text1.size() < text2.size()) {
+            return longestCommonSubsequence(text2, text1);
+        }
+        vector<vector<int>> dp(2, vector<int>(text2.size() + 1));
+        for (int i = 1; i <= text1.size(); ++i) {
+            for (int j = 1; j <= text2.size(); ++j) {
+                dp[i % 2][j] = (text1[i - 1] == text2[j - 1])
+                               ? dp[(i - 1) % 2][j - 1] + 1
+                               : max(dp[(i - 1) % 2][j], dp[i % 2][j - 1]);
+                               
+            }
+        }
+        return dp[text1.size() % 2][text2.size()];
+    }
+};