Create 790. Domino and Tromino Tiling (#787)

Author: Chayandas07

790. Domino and Tromino Tiling

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+class Solution {
+public:
+    const int MOD = 1e9 + 7;
+    int numTilings(int n) {
+        if (n == 0) return 1;
+        if (n == 1) return 1;
+        if (n == 2) return 2;
+
+        vector<long long> dp(n+1), prefix(n+1);
+        dp[0] = 1;
+        dp[1] = 1;
+        dp[2] = 2;
+        prefix[0] = 1;
+        prefix[1] = 2;
+        prefix[2] = 4;
+
+        for (int i = 3; i <= n; ++i) {
+            dp[i] = (dp[i-1] + dp[i-2] + 2 * prefix[i-3]) % MOD;
+            prefix[i] = (prefix[i-1] + dp[i]) % MOD;
+        }
+
+        return dp[n];
+    }
+};