Adding a new commit

challenges/decode ways.c

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+#include <iostream> 
+#include <cstring> 
+using namespace std; 
+
+// A Dynamic Programming based function  
+// to count decodings 
+int countDecodingDP(char *digits, int n) 
+{ 
+    // A table to store results of subproblems 
+    int count[n+1];  
+    count[0] = 1; 
+    count[1] = 1; 
+    //for base condition "01123" should return 0  
+    if(digits[0]=='0')   
+         return 0; 
+    for (int i = 2; i <= n; i++) 
+    { 
+        count[i] = 0; 
+
+        // If the last digit is not 0,  
+        // then last digit must add to the number of words 
+        if (digits[i-1] > '0') 
+            count[i] = count[i-1]; 
+
+        // If second last digit is smaller  
+        // than 2 and last digit is smaller than 7, 
+        // then last two digits form a valid character  
+        if (digits[i-2] == '1' ||  
+              (digits[i-2] == '2' && digits[i-1] < '7') ) 
+            count[i] += count[i-2]; 
+    } 
+    return count[n]; 
+} 
+
+// Driver program to test above function 
+int main() 
+{ 
+    char digits[] = "1234"; 
+    int n = strlen(digits); 
+    cout << "Count is " << countDecodingDP(digits, n); 
+    return 0; 
+}