C++程序用于找出网格上使用板子着色的方法数
假设,我们得到一个具有2行n列的网格。该网格必须用n个板子覆盖,并且不能有板子重叠。现在,这些板子必须用红色、蓝色和绿色中的任意一种颜色着色。两个相邻的板子不能用相同的颜色着色,并且如果不需要,则不必使用所有颜色。网格的配置在数组'grid'中给出,其中网格中的特定板子用相同的英文字母表示,不同的板子用不同的英文字母表示。我们必须找出可以对板子着色的方法数。
因此,如果输入类似于n = 4,grid = {"abbd", "accd"},则输出将为6。
有6种不同的方法可以对板子着色,以满足给定的条件。
步骤
为了解决这个问题,我们将遵循以下步骤:
MODVAL := 10^9 + 7 Define an array s for initialize i := 0, when i < n, do: if grid[0, i] is same as grid[1, i], then: insert 1 at the end of s (increase i by 1) Otherwise, insert 2 at the end of s i := i + 2 Define an array tvec if s[0] is same as 1, then: tvec[0] := 3 Otherwise, tvec[0] := 6 for initialize i := 1, when i < size of s, update (increase i by 1), do: if s[i - 1] is same as 2 and s[i] is same as 2, then: tvec[i] := tvec[i - 1] * 3 mod MODVAL if s[i - 1] is same as 2 and s[i] is same as 1, then: tvec[i] := tvec[i - 1] if s[i - 1] is same as 1 and s[i] is same as 2, then: tvec[i] := tvec[i - 1] * 2 mod MODVAL if s[i - 1] is same as 1 and s[i] is same as 1, then: tvec[i] := tvec[i - 1] * 2 mod MODVAL return tvec[size of s - 1]
示例
让我们看看以下实现以更好地理解:
#include <bits/stdc++.h> using namespace std; int solve(int n, vector<string> grid){ int MODVAL = 1e9 + 7; vector<int> s; for (int i = 0; i < n;) { if (grid[0][i] == grid[1][i]) { s.push_back(1); i++; } else { s.push_back(2); i += 2; } } vector<int> tvec(s.size()); if (s[0] == 1) tvec[0] = 3; else tvec[0] = 6; for (int i = 1; i < (int)s.size(); i++) { if (s[i - 1] == 2 && s[i] == 2) tvec[i] = tvec[i - 1] * 3 % MODVAL; if (s[i - 1] == 2 && s[i] == 1) tvec[i] = tvec[i - 1]; if (s[i - 1] == 1 && s[i] == 2) tvec[i] = tvec[i - 1] * 2 % MODVAL; if (s[i - 1] == 1 && s[i] == 1) tvec[i] = tvec[i - 1] * 2 % MODVAL; } return tvec[s.size() - 1]; } int main() { int n = 4; vector <string> grid = {"abbd", "accd"}; cout<< solve(n, grid); return 0; }
输入
4, {"abbd", "accd"}
输出
6
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