面试题12:矩阵中的路径

题目描述

判断矩阵中是否存在一条包含某个字符串所有字符的路径

回溯，判断上下左右

bool hasPath(char *matrix, int rows, int cols, char *str)
{
	if(matrix == nullptr || rows<1 || cols < 1 ||str == nullptr)
	{
		return false;
	}
	bool *visited = new bool[rows*cols];
	memset(visited, 0, rows*cols);
	int pathLength = 0;
	for(int row=0; row<rows; row++)
	{
		for(int col=0; col<cols; col++)
		{
			if(hasPathCore(matrix, rows, cols, row, col, str, pathLength, visited))
			return true;
		}
	}
	delete []visited;
	return false;
}

bool hasPathCore(char *matrix, int rows, int cols, int row,int  col, char *str,int  pathLength, bool *visited)
{
	if(str[pathLength]=='\0')
		return true;
	bool hasPath = false;
	if(row >=0 && row <rows && col >=0 && col<cols && maxtrix[row][col] == str[pathLength]&& !visited[row*cols +col])
	{
		visited[row*cols +col] = true;
		pathLength++;
	}
	hasPath = hasPathCore(matrix, rows, cols, row+1, col, str, pathLength, visited) ||hasPathCore(matrix, rows, cols, row, col+1, str, pathLength, visited) || hasPathCore(matrix, rows, cols, row-1, col, str, pathLength, visited) || hasPathCore(matrix, rows, cols, row, col-1, str, pathLength, visited)
	if(!hasPath)
	{
		pathLength --;
		visited[row*cols +col] = false;
	}
	return hasPath;
}