题目描述
地上有一个m行和n列的方格。一个机器人从坐标0,0的格子开始移动,每一次只能向左,右,上,下四个方向移动一格,但是不能进入行坐标和列坐标的数位之和大于k的格子。 例如,当k为18时,机器人能够进入方格(35,37),因为3+5+3+7 = 18。但是,它不能进入方格(35,38),因为3+5+3+8 = 19。请问该机器人能够达到多少个格子?
class Solution {
public:
int movingCount(int threshold, int rows, int cols)
{
bool *vist = new bool[rows * cols];
memset(vist, 0, rows * cols);
int row = 0, col = 0;
int cnt = 0;
gridCnt(threshold, rows, cols, row, col, cnt, vist);
return cnt;
}
void gridCnt(int threshold, int rows, int cols, int row, int col, int &cnt, bool *vist) //注意这里的 cnt 为引用
{
if(row < rows && row >=0 && col < cols && col >= 0
&& threshold >= coordSum(row, col) && !vist[row * cols + col])
{
++cnt;
vist[row * cols + col] = true;
gridCnt(threshold, rows, cols, row + 1, col, cnt, vist);
gridCnt(threshold, rows, cols, row, col + 1, cnt, vist);
gridCnt(threshold, rows, cols, row - 1, col, cnt, vist);
gridCnt(threshold, rows, cols, row, col - 1, cnt, vist);
}
}
int coordSum(int rows, int cols) //计算坐标和
{
int sum = 0;
while(rows > 0 || cols > 0)
{
sum += rows % 10 + cols % 10;
rows = rows / 10;
cols = cols / 10;
}
return sum;
}
};