uva 10267 Graphical Editor

最新推荐文章于 2018-02-22 09:12:06 发布

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这篇博客讨论了ACM竞赛中UVA 10267题目的解题思路，强调在实现图形编辑器的填充区域功能时，使用深度优先搜索（DFS）而非广度优先搜索（BFS），以避免超时问题。

简单练习题目，注意用广搜会超时，完成填充区域功能的时候用深搜。

#include <stdio.h>
#include <queue>
using namespace std;

#define		MAX_LEN		300

char image[MAX_LEN][MAX_LEN];
int M, N;
/*
struct pos
{
	int i;
	int j;
};
*/
void ins_I(int m, int n)
{
	int i, j;

	M = m;
	N = n;

	for(i=1; i<=M; i++)
		for(j=1; j<=N; j++)
			image[i][j] = 'O';
}


void ins_C(void)
{
	int i, j;

	for(i=1; i<=M; i++)
		for(j=1; j<=N; j++)
			image[i][j] = 'O';
}

void ins_L(int x, int y, char color)
{
	image[y][x] = color;
}

void ins_V(int x, int y1, int y2, char color)
{
	int i;
	int t;

	if(y1 > y2)
	{
		t = y1;
		y1 = y2; 
		y2 = t;
	}
	
	for(i=y1; i<=y2; i++)
		image[i][x] = color;
}

void ins_H(int x1, int x2, int y, char color)
{
	int i;
	int t;

	if(x1 > x2)
	{
		t = x1;
		x1 = x2; 
		x2 = t;
	}

	for(i=x1; i<=x2; i++)
		image[y][i] = color;
}

void ins_K(int x1, int y1, int x2, int y2, char color)
{
	int i, j;

	for(i=y1; i<=y2; i++)
		for(j=x1; j<=x2; j++)
		{
			image[i][j] = color;
		}
}
/*
//用广度优先搜索会超时
queue<struct pos> q;
char original_color;
char change_color;
struct pos p;
void bfs(int i, int j)
{
	p.i = i;
	p.j = j;
	q.push(p);
	while(1)
	{
		i = q.front().i;
		j = q.front().j;
		image[i][j] = change_color;
		q.pop();
	
		if(i-1>=1 && image[i-1][j] == original_color)
		{
			p.i = i-1;
			p.j = j;
			q.push(p);
		}

		if(i+1<=M && image[i+1][j] == original_color)
		{
			p.i = i+1;
			p.j = j;
			q.push(p);
		}

		if(j-1>=1 && image[i][j-1] == original_color)
		{
			p.i = i;
			p.j = j-1;
			q.push(p);
		}

		if(j+1<=N && image[i][j+1] == original_color)
		{
			p.i = i;
			p.j = j+1;
			q.push(p);
		}

		if(q.empty())
			break;
	}
}
*/

char original_color;
char change_color;
void dfs(int i, int j)
{
	if(i<1 || i>M)
		return;
	if(j<1 || j>N)
		return;

	image[i][j] = change_color;

	if(image[i-1][j] == original_color)
		dfs(i-1, j);
	if(image[i+1][j] == original_color)
		dfs(i+1, j);
	if(image[i][j-1] == original_color)
		dfs(i, j-1);
	if(image[i][j+1] == original_color)
		dfs(i, j+1);
}


void ins_F(int x, int y, char color) //广搜填充区域
{
	int i, j;

	i = y;
	j = x;

	original_color = image[i][j];
	change_color = color;
	if(change_color != original_color)
		dfs(i, j);
}

void ins_S(char *name)
{
	int i, j;

	printf("%s\n", name);

	for(i=1; i<=M; i++)
	{
		for(j=1; j<=N; j++)
		{
			printf("%c", image[i][j]);
		}
		printf("\n");
	}
}

int main(void)
{
	char cmd, color;
	int x, y, x1, y1, x2, y2;
	int m, n;
	char name[100];
	char buffer[200];

	while(1)
	{
		gets(buffer);
		
		switch(buffer[0])
		{
		case 'I':
			sscanf(buffer, "%c %d %d", &cmd, &n, &m);
			//printf("%c %d %d\n", cmd, m, n);
			ins_I(m, n);
			break;
		case 'C':
			sscanf(buffer, "%c", &cmd);
			//printf("%c\n", cmd);
			ins_C();
			break;
		case 'L':
			sscanf(buffer, "%c %d %d %c", &cmd, &x, &y, &color);
			//printf("%c %d %d %c\n", cmd, x, y, color);
			ins_L(x, y, color);
			break;
		case 'V':
			sscanf(buffer, "%c %d %d %d %c", &cmd, &x, &y1, &y2, &color);
			//printf("%c %d %d %d %c\n", cmd, x, y1, y2, color);
			ins_V(x, y1, y2, color);
			break;
		case 'H':
			sscanf(buffer, "%c %d %d %d %c", &cmd, &x1, &x2, &y, &color);
			//printf("%c %d %d %d %c\n", cmd, x1, x2, y, color);
			ins_H(x1, x2, y, color);
			break;
		case 'K':
			sscanf(buffer, "%c %d %d %d %d %c", &cmd, &x1, &y1, &x2, &y2, &color);
			//printf("%c %d %d %d %c\n", cmd, x1, y1, x2, y2, color);
			ins_K(x1, y1, x2, y2, color);
			break;
		case 'F':
			sscanf(buffer, "%c %d %d %c", &cmd, &x, &y, &color);
			//printf("%c %d %d %c\n", cmd, x, y, color);
			ins_F(x, y, color);
			break;
		case 'S':
			sscanf(buffer, "%c %s", &cmd, name);
			//printf("%c %s\n", cmd, name);
			ins_S(name);
			break;
		case 'X':
			//sscanf(buffer, "%c", &cmd);
			//printf("%c\n", cmd);
			goto end; 
			break;
		}
	}
end:
	return 0;
}