2

Author: kedebug

DistinctSubsequences/DistinctSubsequences.cpp

@@ -0,0 +1,26 @@
+class Solution {
+public:
+    int numDistinct(string S, string T) {
+        // Start typing your C/C++ solution below
+        // DO NOT write int main() function
+        
+        int M = S.size();
+        int N = T.size();
+        
+        if (M == 0 && N == 0)
+            return 1;
+        else if (M < N)
+            return 0;
+            
+        int F[N+1];
+        memset(F, 0, sizeof(int)*(N+1));
+        F[0] = 1;
+        for (int i = 1; i <= M; i++) {
+            for (int j = N; j >= 1; j--) {
+                if (S[i-1] == T[j-1])
+                    F[j] = F[j-1] + F[j];
+            }
+        }
+        return F[N];
+    }
+};