fix: updated problem output since the numbers of combinations could be very high.

decode-ways/src/TLE.cpp

@@ -3,7 +3,9 @@
 typedef long long ll;
 using namespace std;
 
-int ways(string &s, int n, int idx = 0)
+const int MOD = 1e9 + 7;
+
+ll ways(string &s, int n, int idx = 0)
 {
     if (idx > n)
         return 1;
@@ -14,11 +16,13 @@ int ways(string &s, int n, int idx = 0)
     if (idx + 1 < n)
     {
         int num = stoi(s.substr(idx, 2));
-        if (num >= 10 && num <= 26)
+        if (num >= 10 && num <= 26){
             count += ways(s, n, idx + 2);
+            count %= MOD;
+        }
     }
 
-    return count;
+    return count % MOD;
 }
 
 vector<bool> used;

decode-ways/src/ac.cpp

@@ -3,6 +3,8 @@
 typedef long long ll;
 using namespace std;
 
+const int MOD = 1e9 + 7;
+
 ll numDecodings(string s)
 {
    if (s[0] == '0')
@@ -36,15 +38,17 @@ ll numDecodings(string s)
       if (current != '0')
       {
          dp[i][0] = dp[i - 1][0] + dp[i - 1][1];
+         dp[i][0] %= MOD;
       }
 
       int code = stoi(aux);
       if (10 <= code && code <= 26)
       {
          dp[i][1] = dp[i - 2][0] + dp[i - 2][1];
+         dp[i][1] %= MOD;
       }
    }
-   return dp[N][0] + dp[N][1];
+   return (dp[N][0] + dp[N][1]) % MOD;
 }
 
 int main()

decode-ways/src/alternative-ac2.py

@@ -13,4 +13,4 @@ for i in range(1, n + 1):
         if 10 <= two_digit <= 26:
             dp[i] += dp[i - 2]
 
-print(dp[n])
+print(dp[n] % 1000000007)

decode-ways/src/alternative_ac.cpp

@@ -3,6 +3,8 @@
 typedef long long ll;
 using namespace std;
 
+const int MOD = 1e9 + 7;
+
 ll numDecodings(string s)
 {
     if (s[0] == '0')
@@ -20,12 +22,14 @@ ll numDecodings(string s)
         if (current != '0')
         {
             next = dp2;
+            next %= MOD;
         }
 
         int code = stoi(aux);
         if (10 <= code && code <= 26)
         {
             next += dp1;
+            next %= MOD;
         }
         swap(dp1, dp2);
         swap(dp2, next);