ACODE - Alphacode

Author: amitbansal7

SPOJ/ACODE.cpp

@@ -0,0 +1,57 @@
+/* Amit Bansal - @amitbansal7 */
+#include <bits/stdc++.h>
+#include <string>
+#define lli long long int
+#define llu unsigned long long int
+#define S(x) scanf("%d",&x)
+#define Sl(x) scanf("%lld",&x)
+#define Mset(p,i) memset(p,i,sizeof(p))
+#define mlc(t,n) (t *)malloc(sizeof(t)*n)
+#define NIL -1
+#define INF INT_MAX
+#define TC int testcase; S(testcase); while(testcase--)
+#define Pi 3.14159
+using namespace std;
+
+bool valid(char c){ return c!='0'; }
+bool valid(char a,char b){ return a=='1' || (a=='2' && b<='6'); }
+
+llu solve(string s,int i,llu DP[])
+{
+    if(i<=1)
+        return 1;
+
+    if(DP[i] != -1)
+        return DP[i];
+
+    llu a = 0;
+    char b = s[i-1];
+    char c = s[i-2];
+    if(valid(b))
+        a = solve(s,i-1,DP);
+
+    if(valid(c,b))
+        a += solve(s,i-2,DP);
+
+    return DP[i] = a;
+}
+
+int main(int argc, char const *argv[])
+{
+    string s;
+    while(1)
+    {
+        cin>>s;
+        if(s[0] == '0')
+            break;
+
+        llu DP[s.size()+1];
+        for(int i=0;i<=s.size();i++)
+            DP[i] = -1;
+
+        llu ans = solve(s,s.size(),DP);
+        cout<<ans<<endl;
+    }
+
+    return 0;
+}