add code

Author: ncdhz

code/790.多米诺和托米诺平铺.cpp

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+/*
+ * @lc app=leetcode.cn id=790 lang=cpp
+ *
+ * [790] 多米诺和托米诺平铺
+ */
+#include <map>
+using namespace std;
+// @lc code=start
+class Solution {
+ int max_value = 1000000007;
+ map<int, int> cache;
+public:
+ int numTilings(int n) {
+ if (n == 0) {
+ return 1;
+ }
+ 
+ if (cache.count(n) > 0) {
+ return cache.at(n);
+ }
+ 
+ long x = 0;
+ x += numTilings(n - 1);
+ if (n >= 2) {
+ x += numTilings(n - 2);
+ }
+ 
+ for (size_t i = 3; i <= n; i++) {
+ x += 2 * numTilings(n - i);
+ }
+ 
+ int r = (int)(x % max_value);
+ 
+ auto pr = make_pair(n, r);
+
+ cache.insert(pr);
+ return r;
+ }
+};
+// @lc code=end
+