POJ2676 Sudoku

Posted 2020-11-02 COLORFUL

题意：数独

题解：dfs.dfs前判断能否填。

　　判断方法：用三个数组。

 

#define _CRT_SECURE_NO_WARNINGS
#include<cstring>
#include<cctype>
#include<cstdlib>
#include<cmath>
#include<cstdio>
#include<string>
#include<stack>
#include<ctime>
#include<list>
#include<set>
#include<map>
#include<queue>
#include<vector>
#include<sstream>
#include<iostream>
#include<functional>
#include<algorithm>
#include<memory.h>
//#define INF 0x3f3f3f3f
#define eps 1e-6
#define pi acos(-1.0)
#define e exp(1.0)
#define rep(i,t,n)  for(int i =(t);i<=(n);++i)
#define per(i,n,t)  for(int i =(n);i>=(t);--i)
#define mp make_pair
#define pb push_back
#define mmm(a,b) memset(a,b,sizeof(a))
//std::ios::sync_with_stdio(false);
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
void smain();
#define ONLINE_JUDGE
int main() {
//    ios::sync_with_stdio(false);
#ifndef ONLINE_JUDGE
    freopen("in.txt", "r", stdin);
    freopen("out.txt", "w", stdout);
    long _begin_time = clock();
#endif
    smain();
#ifndef ONLINE_JUDGE
    long _end_time = clock();
    printf("time = %ld ms.", _end_time - _begin_time);
#endif
    return 0;
}
int  rowflag[9][10], colflag[9][10], blockflag[9][10];
int board[9][9];
struct pos {
    int r, c;
    pos(int rr, int cc) :r(rr), c(cc) {}
};
vector<pos> blankpos;
inline int GetBlockNum(int r, int c) {
    int rr = r / 3;
    int cc = c / 3;
    return rr * 3 + cc;
}
void SetAllFlags(int r, int c, int num, int f) {
    rowflag[r][num] = f;
    colflag[c][num] = f;
    blockflag[GetBlockNum(r, c)][num] = f;
}
bool isOK(int r, int c, int num) {
    return !rowflag[r][num] && !colflag[c][num] && !blockflag[GetBlockNum(r, c)][num];

}
bool  dfs(int n) {//处理前n个
    if (n < 0) return 1;
    int r = blankpos[n].r;
    int c = blankpos[n].c;
    rep(num, 1, 9) {
        if (isOK(r, c, num)) {
            board[r][c] = num;
            SetAllFlags(r, c, num, 1);
            if (dfs(n - 1)) return 1;
            SetAllFlags(r, c, num, 0);
        }
    }
    return 0;
}
void Run() {
    mmm(rowflag, 0);
    mmm(colflag, 0);
    mmm(blockflag, 0);
    blankpos.clear();
    rep(i, 0, 8)rep(j, 0, 8) {
        char c;
        cin >> c;
        board[i][j] = c - ‘0‘;
        if (board[i][j])SetAllFlags(i, j, board[i][j], 1);
        else blankpos.push_back(pos(i, j));
}
    
    if (dfs(blankpos.size()-1 ) ){
        rep(i, 0, 8) {
            rep(j, 0, 8) cout <<char( board[i][j]+‘0‘);
            cout << endl;
        }
        
    }
}

void smain() {
    int t;
    cin >> t;
    while (t--) {
        Run();
    }
}