ACM： ICPC/CCPC Sudoku DFS - 数独

最新推荐文章于 2019-06-13 19:18:57 发布

转载最新推荐文章于 2019-06-13 19:18:57 发布 · 143 阅读

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原文链接：http://www.cnblogs.com/HDMaxfun/p/5868983.html

本文介绍了一个简化版的数独游戏，尺寸为4x4，并且每个2x2的小区域也必须包含1到4的数字。文章提供了一种通过回溯算法解决这个问题的方法，并分享了AC代码。

Sudoku

Time Limit : 3000/1000ms (Java/Other) Memory Limit : 65535/65535K (Java/Other)

Total Submission(s) : 19 Accepted Submission(s) : 5

Problem Description

Yi Sima was one of the best counselors of Cao Cao. He likes to play a funny game himself. It looks like the modern Sudoku, but smaller.

Actually, Yi Sima was playing it different. First of all, he tried to generate a $4×4$ board with every row contains 1 to 4, every column contains 1 to 4. Also he made sure that if we cut the board into four $2×2$ pieces, every piece contains 1 to 4.

Then, he removed several numbers from the board and gave it to another guy to recover it. As other counselors are not as smart as Yi Sima, Yi Sima always made sure that the board only has one way to recover.

Actually, you are seeing this because you've passed through to the Three-Kingdom Age. You can recover the board to make Yi Sima happy and be promoted. Go and do it!!!

Input

The first line of the input gives the number of test cases, $T(1≤T≤100)$. $T$ test cases follow. Each test case starts with an empty line followed by 4 lines. Each line consist of 4 characters. Each character represents the number in the corresponding cell (one of '1', '2', '3', '4'). '*' represents that number was removed by Yi Sima. It's guaranteed that there will be exactly one way to recover the board.

Output

For each test case, output one line containing [b]Case #x:[/b], where $x$ is the test case number (starting from 1). Then output 4 lines with 4 characters each. indicate the recovered board.

Sample Input

****

2341

4123

3214

*243

*312

*421

*134

*41*

**3*

2*41

4*2*

Sample Output

Case #1:

1432

2341

4123

3214

Case #2:

1243

4312

3421

2134

Case #3:

3412

1234

2341

4123

Source

The 2015 China Collegiate Programming Contest

/*/
最进学校的课真是让人崩溃啊，作业都快做不过来了，挤个下午刷刷题目，却被一个做过的题目卡了好久，我的天啊。。

题意：
这个题目就是数独，但是是4*4的数独。

补全这个数独。。

一开始少读了一句 2x2 也要保持独立性，WA了一发。。。

AC代码：
/*/

#include "iostream"
#include "cstdio"
#include "cstring"
#include "string"
#include "cmath"
using namespace std;
typedef long long LL;
#define memset(x,y) memset(x,y,sizeof(x))
#define memcpy(x,y) memcpy(x,y,sizeof(x))

const int MX = 1e5 + 100 ;
int _;
int vix[5][5] ,viy[5][5],IXI[3][3][5],maps[5][5];
char tem[5][5];
int flag;

void _X_() {
	puts("");
	puts("");
	puts("");
}

void Print() {
	for(int i=0; i<4; i++) {
		for(int j=0; j<4; j++) {
			printf("%d",maps[i][j]);
		}
		puts("");
	}
}

void init() {
	flag=0;
	_=0;
	memset(vix,0);
	memset(viy,0);
	memset(IXI,0);
}

int DFS(int i,int j,int __) {
	if(__==_) {
		return flag=1;
	}
	if(tem[i][j]=='*') {
		for(int k=1; k<=4; k++) {
			if(vix[j][k]||viy[i][k]||flag||IXI[i/2][j/2][k])continue;
//			cout<< __ <<"["<<k<<"]";
			maps[i][j]=k;
			vix[j][k]=1;
			viy[i][k]=1;
			IXI[i/2][j/2][k]=1;
			if(j<3) DFS(i,j+1,__+1);
			else if(i<3) DFS(i+1,0,__+1);
			else if(i==3&&j==3) {
				DFS(3,3,__+1);
			}
			if(flag)break;
			maps[i][j]=0;
			vix[j][k]=0;
			viy[i][k]=0;
			IXI[i/2][j/2][k]=0;
		}
	}
	if(j<3) DFS(i,j+1,__);
	else if(i<3) DFS(i+1,0,__);
	return 0;
}

int main() {
	int T;
	while(~scanf("%d",&T)) {
		for(int qq=1; qq<=T; qq++) {
			init();
			for(int i=0; i<4; i++) {
				cin>>tem[i];
				for(int j=0; j<4; j++) {
					if(tem[i][j]=='*') {
						maps[i][j]=0;
						_++;
					} else {
						maps[i][j]=tem[i][j]-'0';
						vix[j][maps[i][j]]=1;
						viy[i][maps[i][j]]=1;
						IXI[i/2][j/2][maps[i][j]]=1;
					}
				}
			}
//			cout<<_<<endl;
//			_X_();
			DFS(0,0,0);
			printf("Case #%d:\n",qq);
			Print();
//			_X_();
		}
	}
	return 0;
}

转载于:https://www.cnblogs.com/HDMaxfun/p/5868983.html