1317. Sudoku

Problem-solving skills: 1. The number of Sudoku per grid record itself can fill the number, each search can fill the number of the minimum number of lattice fill numbers.

2. Use "Disable Count" to record the number of times a number is disabled for each lattice so that it can be resumed after disabling.

#include <cstdio> #include <cstring> #include <set> #include <vector>using std::set;using std::    vector;struct Elem {int num; Set<int> lefts;}; set<int> lefts;const int maxn = 9;char charmap[maxn][maxn+1];    Elem map[maxn][maxn];int ans[maxn][maxn];int count;int f[maxn][maxn][maxn + 1];struct Cor {int R, C; Cor (int r_ = 0, int c_ = 0): R (R_), C (C_) {} bool operator< (const Cor &cor) Const {return (R < COR.R ) ||    (r = = COR.R && c < cor.c);            }};set<cor> unfills;void Init () {for (int i = 0, i < MAXN; ++i) {for (int j = 0; j < Maxn; ++j) {            Map[i][j].num = 0;        Map[i][j].lefts.insert (Lefts.begin (), Lefts.end ());  }} for (int i = 0, i < MAXN; ++i) {for (int j = 0; j < Maxn; ++j) {for (int k = 0; K < MAXN;            ++k) {f[i][j][k + 1] = 0;    }}} count = 0; Unfills.clear ();} void input () {for (int i = 0; i < MAXN;    ++i) {scanf ("%s", Charmap[i]);            }}void transform () {for (int i = 0; i < MAXN, ++i) {for (int j = 0; Charmap[i][j]! = '; ++j ') {            if (charmap[i][j]! = ' _ ') {Map[i][j].num = charmap[i][j]-' 0 ';            } else {Unfills.insert (Cor (i, j));    }}}}void setting (int r, int c, int num) {map[r][c].num = num;        for (int i = 0; i < MAXN; ++i) {map[r][i].lefts.erase (num);        ++f[r][i][num];        Map[i][c].lefts.erase (num);    ++f[i][c][num];    } int beginr = R/3 * 3;    int beginc = C/3 * 3; for (int i = 0, i < 3; ++i) {for (int j = 0; j < 3; ++j) {map[i + beginr][j + Beginc].lefts.eras            E (NUM);        ++f[i + beginr][j + beginc][num];    }}}void Resume (int r, int c, int num) {map[r][c].num = 0;        for (int i = 0; i < MAXN; ++i) {if (--f[r][i][num] = = 0) map[r][i].lefts.insert (num); if (--f[i][c][num] = = 0) map[i][c].lefts.insert (num);    } int beginr = R/3 * 3;    int beginc = C/3 * 3;  for (int i = 0, i < 3; ++i) {for (int j = 0; j < 3; ++j) {if (--f[i+beginr][j+beginc][num] = = 0)        Map[i + beginr][j + beginc].lefts.insert (num); }}}void Predeal () {for (int i = 0, i < MAXN; ++i) {for (int j = 0; j < Maxn; ++j) {if (M            Ap[i][j].num! = 0) {Setting (I, J, Map[i][j].num);        }}}}void Dfs () {if (Unfills.empty ()) {///To achieve a destination state ++count;        if (Count > 1) return; for (int i = 0, i < MAXN; ++i) {for (int j = 0; j < Maxn; ++j) {Ans[i][j] = map[i][j].nu            M }}} else {//traverse unfills, look for the smallest set<cor>::iterator iter = Unfills.begin (), target = Unfills.        Begin ();            while (iter! = Unfills.end ()) {const Cor &cor1 = *iter;   Const Cor &AMP;COR2 = *target;         if (Map[cor1.r][cor1.c].lefts.size () < Map[cor2.r][cor2.c].lefts.size ()) {target = iter;        } ++iter;        } Cor cor = *target;        Unfills.erase (target);   Set<int> _lefts (map[cor.r][cor.c].lefts);        Set<int>::iterator iter1 = _lefts.begin ();            while (Iter1! = _lefts.end ()) {int num = *iter1;            Setting (COR.R, COR.C, num);            DFS ();            Resume (COR.R, cor.c, num);        ++iter1;    } unfills.insert (COR);    }}int Main () {for (int i = 1; I <= 9; ++i) Lefts.insert (i);    int t;    scanf ("%d", &t);        for (int tt = 1; TT <= t; ++tt) {//Initialize init ();        Enter input ();        Conversion transform ();        Pretreatment predeal ();        Deep Search DFS ();        if (count = = 0) {printf ("Puzzle%d has no solution\n", TT); } else if (count = = 1) {printf ("Puzzle%d solution is\n", TT); for (int i = 0; i < MAXN; ++i) {for (int j = 0; j < Maxn; ++j) {printf ("%d", ans I                [j]);            } printf ("\ n");        }} else if (Count > 1) {printf ("Puzzle%d has%d solutions\n", TT, Count);    } if (tt! = t) printf ("\ n"); } return 0;}

　　

1317. Sudoku