48 lines
1.1 KiB
C++
48 lines
1.1 KiB
C++
#include <iostream>
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#include <cstdio>
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#include <algorithm>
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#include <cmath>
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#include <cstring>
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#include <queue>
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#include <stack>
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//notice the '#' can be placed.
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using namespace std;
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const int MAXN = 10;
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int n, m;
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int ans = 0;
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char my_map[MAXN][MAXN];
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bool vis_row[MAXN]; //vis_row[i], i row is visited.
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bool vis_col[MAXN]; //vis_col[j], j col is visited.
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bool judge(int x, int y){
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if(x<0 || x>=n || y<0 || y>=n || my_map[x][y]!='#') return false;
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if(vis_row[x] || vis_col[y]) return false;
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return true;
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}
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void DFS(int x, int y, int step){
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//int xx, yy;
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if(step == m) {ans++; return;}
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for(int i=x; i<n; i++)
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for(int j=0; j<n; j++){
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if(judge(i, j)){
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vis_row[i] = vis_col[j] = true;
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DFS(i, j, step+1);
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vis_row[i] = vis_col[j] = false;
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}
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}
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}
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int main(){
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while(scanf("%d%d", &n, &m) && n!=-1 && m!=-1){
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ans = 0;
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memset(vis_row, false, sizeof(vis_row));
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memset(vis_col, false, sizeof(vis_col));
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for(int i=0; i<n; i++) scanf("%s", my_map[i]);
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DFS(0, 0, 0);
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printf("%d\n", ans);
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}
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return 0;
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}
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