LRproblem.c

#include<stdio.h>

//#define DEBUG
#ifdef DEBUG
unsigned long long int count = 0;
#endif


struct Node
{
	struct Node *preNode;
	struct Node *nextNode;
	char value;
}root;


void ShowParent(struct Node*);
void Create(struct Node *node, int l, int r);


int main()
{
	int l, r;

	while (1)
	{
		printf("¥nInput L and R.¥nIf you enter a negative value, this program will close.¥n");
		printf("L = "); scanf("%d", &l);
		printf("R = "); scanf("%d", &r);
		puts("");
		if (l < 0 || r < 0)
			return 0;
		root.preNode = NULL;
		Create(&root, l, r);

#ifdef DEBUG
		printf("¥n-----------------------¥ncount = %llu¥n-----------------------¥n¥n¥n¥n", count);
		count = 0LL;
#endif
	}
}


void ShowParent(struct Node *node)
{
	printf("%c", node->value);
	if (node->preNode != NULL)
		ShowParent(node->preNode);
}


void Create(struct Node *node, int l, int r)
{
	struct Node nextNode = { NULL, NULL, '¥0' };
	if (l > 0)
	{
		node->value = 'L';
		node->nextNode = &nextNode;
		node->nextNode->preNode = node;
		Create(node->nextNode, l - 1, r);
	}
	if (r > 0)
	{
		node->value = 'R';
		node->nextNode = &nextNode;
		node->nextNode->preNode = node;
		Create(node->nextNode, l, r - 1);
	}
	if (node->value == 'L' || node->value == 'R')
		return;
	ShowParent(node->preNode);
#ifdef DEBUG
	++count;
#endif
	puts("");
}