poj2676 Sudoku

Sudoku

Time Limit: 2000MS		Memory Limit: 65536K
Total Submissions: 17953		Accepted: 8688		Special Judge

Description

Sudoku is a very simple task. A square table with 9 rows and 9 columns is divided to 9 smaller squares 3x3 as shown on the Figure. In some of the cells are written decimal digits from 1 to 9. The other cells are empty. The goal is to fill the empty cells with decimal digits from 1 to 9, one digit per cell, in such way that in each row, in each column and in each marked 3x3 subsquare, all the digits from 1 to 9 to appear. Write a program to solve a given Sudoku-task.

Input

The input data will start with the number of the test cases. For each test case, 9 lines follow, corresponding to the rows of the table. On each line a string of exactly 9 decimal digits is given, corresponding to the cells in
this line. If a cell is empty it is represented by 0.

Output

For each test case your program should print the solution in the same format as the input data. The empty cells have to be filled according to the rules. If solutions is not unique, then the program may print any one of them.

Sample Input

1
103000509
002109400
000704000
300502006
060000050
700803004
000401000
009205800
804000107

Sample Output

143628579
572139468
986754231
391542786
468917352
725863914
237481695
619275843
854396127

Source

Southeastern Europe 2005

最近重装电脑，换成linux的ubuntu系统，还学了emacs的一点皮毛，被弄的晕头转向。。。

题目要ac倒是没有什么难度，最裸的暴力，没有加什么剪枝。分分钟水过。

15854066

ksq2013

2676

Accepted

704K

844MS

G++

1849B

2016-07-30 21:30:13

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<iostream>
using namespace std;
int thd[4]={0,3,6,9},sdk[10][10];
bool col[10][10],row[10][10];
bool jud(int x,int y,int z)
{
    int xs,xt,ys,yt;
    for(int i=1;i<=3;i++)
        if(x<=thd[i]){
            xs=thd[i-1]+1;
            xt=thd[i];
            break;
        }
    for(int i=1;i<=3;i++)
        if(y<=thd[i]){
            ys=thd[i-1]+1;
            yt=thd[i];
            break;
        }
    for(int i=xs;i<=xt;i++)
        for(int j=ys;j<=yt;j++)
            if(!(sdk[i][j]^z))
                return false;//this answer is ;
    return true;
}
bool dfs()
{
    for(int i=1;i<=9;i++)
        for(int j=1;j<=9;j++)
            if(!sdk[i][j]){
                for(int k=1;k<=9;k++){
                    if((!col[j][k])&&(!row[i][k])&&jud(i,j,k)){
                        sdk[i][j]=k;
                        col[j][k]=row[i][k]=1;
                        if(dfs())return true;//selected the right answer;
                        col[j][k]=row[i][k]=0;
                        sdk[i][j]=0;
                    }
                }
                return false;//it was impossible to deduce an answer in a certain unit,then it's unreachable;
            }
    return true;//the units were filled correctly;
}
int main()
{
    int T;
    scanf("%d",&T);
    while(T--){
        memset(col,false,sizeof(col));
        memset(row,false,sizeof(row));
        for(int i=1;i<=9;i++)
            for(int j=1;j<=9;j++){
                char ch;
                cin>>ch;
                sdk[i][j]=ch-'0';
                col[j][sdk[i][j]]=true;
                row[i][sdk[i][j]]=true;//Init();
            }
        dfs();
        for(int i=1;i<=9;i++){
            for(int j=1;j<=9;j++)
                printf("%d",sdk[i][j]);
            putchar('\n');
        }
    }
    return 0;
}

看了网上的题解后，发现反着搜，即从右下角向左上角搜更快逼近正解，于是稍稍修改了程序，果然快了许多倍。

15854143

ksq2013

2676

Accepted

704K

16MS

G++

1849B

2016-07-30 21:44:56

#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<iostream>
using namespace std;
int thd[4]={0,3,6,9},sdk[10][10];
bool col[10][10],row[10][10];
bool jud(int x,int y,int z)
{
    int xs,xt,ys,yt;
    for(int i=1;i<=3;i++)
        if(x<=thd[i]){
            xs=thd[i-1]+1;
            xt=thd[i];
            break;
        }
    for(int i=1;i<=3;i++)
        if(y<=thd[i]){
            ys=thd[i-1]+1;
            yt=thd[i];
            break;
        }
    for(int i=xs;i<=xt;i++)
        for(int j=ys;j<=yt;j++)
            if(!(sdk[i][j]^z))
                return false;//this answer is ;
    return true;
}
bool dfs()
{
    for(int i=9;i>=1;i--)
        for(int j=9;j>=1;j--)
            if(!sdk[i][j]){
                for(int k=1;k<=9;k++){
                    if((!col[j][k])&&(!row[i][k])&&jud(i,j,k)){
                        sdk[i][j]=k;
                        col[j][k]=row[i][k]=1;
                        if(dfs())return true;//selected the right answer;
                        col[j][k]=row[i][k]=0;
                        sdk[i][j]=0;
                    }
                }
                return false;//it was impossible to deduce an answer in a certain unit,then it's unreachable;
            }
    return true;//the units were filled correctly;
}
int main()
{
    int T;
    scanf("%d",&T);
    while(T--){
        memset(col,false,sizeof(col));
        memset(row,false,sizeof(row));
        for(int i=1;i<=9;i++)
            for(int j=1;j<=9;j++){
                char ch;
                cin>>ch;
                sdk[i][j]=ch-'0';
                col[j][sdk[i][j]]=true;
                row[i][sdk[i][j]]=true;//Init();
            }
        dfs();
        for(int i=1;i<=9;i++){
            for(int j=1;j<=9;j++)
                printf("%d",sdk[i][j]);
            putchar('\n');
        }
    }
    return 0;
}