poj 2676 Sudoku(dfs)

来源：互联网发布：死亡代理人知乎编辑：程序博客网时间：2024/05/31 19:08
用一个数组把空位记录下来，直接搜索就好了
#include <cstdio>#include <cstring>struct node{    int x,y;};node ns[100];int len;char g[10][10];bool flag;bool check(int k, int index){    int x = ns[index].x;    int y = ns[index].y;    int cx = (x/3)*3+1;    int cy = (y/3)*3+1;//当前所在子矩阵的中心坐标    int mark = false;    for(int i = 0; i < 9; ++i)    {        if(g[x][i] == k)        {            mark = true;            break;        }        if(g[i][y] == k)        {            mark = true;            break;        }    }    if(mark) return false;    if(g[cx][cy] == k || g[cx-1][cy-1] == k || g[cx-1][cy] == k || g[cx][cy-1] == k ||       g[cx+1][cy] == k || g[cx][cy+1] == k || g[cx-1][cy+1] == k || g[cx+1][cy-1] == k ||       g[cx+1][cy+1] == k)        mark = true;    if(mark) return false;    return true;}void DFS(int index){    if(index == len)    {        flag = true;        return;    }    for(int k = 1; k <= 9; ++k)    {        if(check(k+'0',index))        {            g[ns[index].x][ns[index].y] = k+'0';            DFS(index+1);            if(flag) return;            g[ns[index].x][ns[index].y] = '0';        }    }}int main(){    int t;    scanf("%d",&t);    while(t--)    {        flag = false;        len = 0;        for(int i = 0; i < 9; ++i)            for(int j = 0; j < 9; ++j)            {                scanf(" %c",&g[i][j]);                if(g[i][j] == '0')                {                    ns[len].x = i;                    ns[len].y = j;                    ++len;                }            }        DFS(0);        for(int i = 0; i < 9; ++i)        {            for(int j = 0; j < 9; ++j)                printf("%c",g[i][j]);            printf("\n");        }    }    return 0;}
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