|
45 | 45 |
|
46 | 46 | <!-- 这里可写通用的实现逻辑 -->
|
47 | 47 |
|
| 48 | +**方法一:动态规划** |
| 49 | + |
48 | 50 | <!-- tabs:start -->
|
49 | 51 |
|
50 | 52 | ### **Python3**
|
51 | 53 |
|
52 | 54 | <!-- 这里可写当前语言的特殊实现逻辑 -->
|
53 | 55 |
|
54 | 56 | ```python
|
| 57 | +class Solution: |
| 58 | + def numTilings(self, n: int) -> int: |
| 59 | + @cache |
| 60 | + def dfs(i, j): |
| 61 | + if i > n or j > n: |
| 62 | + return 0 |
| 63 | + if i == n and j == n: |
| 64 | + return 1 |
| 65 | + ans = 0 |
| 66 | + if i == j: |
| 67 | + ans = dfs(i + 2, j + 2) + dfs(i + 1, j + 1) + dfs(i + 2, j + 1) + dfs(i + 1, j + 2) |
| 68 | + elif i > j: |
| 69 | + ans = dfs(i, j + 2) + dfs(i + 1, j + 2) |
| 70 | + else: |
| 71 | + ans = dfs(i + 2, j) + dfs(i + 2, j + 1) |
| 72 | + return ans % mod |
| 73 | + |
| 74 | + mod = 10**9 + 7 |
| 75 | + return dfs(0, 0) |
| 76 | +``` |
55 | 77 |
|
| 78 | +```python |
| 79 | +class Solution: |
| 80 | + def numTilings(self, n: int) -> int: |
| 81 | + f = [1, 0, 0, 0] |
| 82 | + mod = 10**9 + 7 |
| 83 | + for i in range(1, n + 1): |
| 84 | + g = [0] * 4 |
| 85 | + g[0] = (f[0] + f[1] + f[2] + f[3]) % mod |
| 86 | + g[1] = (f[2] + f[3]) % mod |
| 87 | + g[2] = (f[1] + f[3]) % mod |
| 88 | + g[3] = f[0] |
| 89 | + f = g |
| 90 | + return f[0] |
56 | 91 | ```
|
57 | 92 |
|
58 | 93 | ### **Java**
|
59 | 94 |
|
60 | 95 | <!-- 这里可写当前语言的特殊实现逻辑 -->
|
61 | 96 |
|
62 | 97 | ```java
|
| 98 | +class Solution { |
| 99 | + public int numTilings(int n) { |
| 100 | + long[] f = {1, 0, 0, 0}; |
| 101 | + int mod = (int) 1e9 + 7; |
| 102 | + for (int i = 1; i <= n; ++i) { |
| 103 | + long[] g = new long[4]; |
| 104 | + g[0] = (f[0] + f[1] + f[2] + f[3]) % mod; |
| 105 | + g[1] = (f[2] + f[3]) % mod; |
| 106 | + g[2] = (f[1] + f[3]) % mod; |
| 107 | + g[3] = f[0]; |
| 108 | + f = g; |
| 109 | + } |
| 110 | + return (int) f[0]; |
| 111 | + } |
| 112 | +} |
| 113 | +``` |
| 114 | + |
| 115 | +### **C++** |
| 116 | + |
| 117 | +```cpp |
| 118 | +class Solution { |
| 119 | +public: |
| 120 | + const int mod = 1e9 + 7; |
| 121 | + |
| 122 | + int numTilings(int n) { |
| 123 | + long f[4] = {1, 0, 0, 0}; |
| 124 | + for (int i = 1; i <= n; ++i) { |
| 125 | + long g[4] = {0, 0, 0, 0}; |
| 126 | + g[0] = (f[0] + f[1] + f[2] + f[3]) % mod; |
| 127 | + g[1] = (f[2] + f[3]) % mod; |
| 128 | + g[2] = (f[1] + f[3]) % mod; |
| 129 | + g[3] = f[0]; |
| 130 | + memcpy(f, g, sizeof(g)); |
| 131 | + } |
| 132 | + return f[0]; |
| 133 | + } |
| 134 | +}; |
| 135 | +``` |
63 | 136 |
|
| 137 | +### **Go** |
| 138 | + |
| 139 | +```go |
| 140 | +func numTilings(n int) int { |
| 141 | + f := [4]int{} |
| 142 | + f[0] = 1 |
| 143 | + const mod int = 1e9 + 7 |
| 144 | + for i := 1; i <= n; i++ { |
| 145 | + g := [4]int{} |
| 146 | + g[0] = (f[0] + f[1] + f[2] + f[3]) % mod |
| 147 | + g[1] = (f[2] + f[3]) % mod |
| 148 | + g[2] = (f[1] + f[3]) % mod |
| 149 | + g[3] = f[0] |
| 150 | + f = g |
| 151 | + } |
| 152 | + return f[0] |
| 153 | +} |
64 | 154 | ```
|
65 | 155 |
|
66 | 156 | ### **...**
|
|
0 commit comments