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  1. /*
  2. * @Author: hungeazy
  3. * @Date:   2025-10-28 13:46:40
  4. * @Last Modified by:   hungeazy
  5. * @Last Modified time: 2025-10-28 15:20:29
  6. */
  7. #include <bits/stdc++.h>
  8. #include <ext/pb_ds/assoc_container.hpp> 
  9. #include <ext/pb_ds/tree_policy.hpp> 
  10. // #pragma GCC optimize("O3")  
  11. // #pragma GCC optimize("unroll-loops")  
  12. // #pragma GCC target("avx2,bmi,bmi2,popcnt,lzcnt")  
  13. using namespace std;
  14. using namespace __gnu_pbds; 
  15. bool M1;
  16. #define fast ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
  17. #define int long long
  18. #define ll long long 
  19. #define ull unsigned long long
  20. #define sz(x) x.size()
  21. #define sqr(x) (1LL * (x) * (x))
  22. #define all(x) x.begin(), x.end()
  23. #define fill(f,x) memset(f,x,sizeof(f))
  24. #define FOR(i,l,r) for(int i=l;i<=r;i++)
  25. #define FOD(i,r,l) for(int i=r;i>=l;i--)
  26. #define debug(x) cout << #x << " = " << x << '\n'
  27. #define ii pair<int,int>
  28. #define iii pair<int,ii>
  29. #define di pair<ii,ii>
  30. #define vi vector<int>
  31. #define vii vector<ii>
  32. #define mii map<int,int>
  33. #define fi first
  34. #define se second
  35. #define pb push_back
  36. #define MOD 1000000007
  37. #define __lcm(a,b) (1ll * ((a) / __gcd((a), (b))) * (b))
  38. #define YES cout << "YES\n"
  39. #define NO cout << "NO\n"
  40. #define MASK(i) (1LL << (i))
  41. #define c_bit(i) __builtin_popcountll(i)
  42. #define BIT(x,i) ((x) & MASK(i))
  43. #define SET_ON(x,i) ((x) | MASK(i))
  44. #define SET_OFF(x,i) ((x) & ~MASK(i))
  45. #define oo 1e18
  46. #define name "ISLAND"
  47. #define endl '\n'
  48. #define memory() cerr << abs(&M2-&M1)/1024.0/1024 << " MB" << endl
  49. #define time() cerr << endl << "-------------Time:" << 1000.0 * clock() / CLOCKS_PER_SEC << "ms." << endl
  50. template<typename T> bool maximize(T &res, const T &val) { if (res < val){ res = val; return true; }; return false; }
  51. template<typename T> bool minimize(T &res, const T &val) { if (res > val){ res = val; return true; }; return false; }
  52. template <class T> using ordered_set = tree <T, null_type, less_equal <T>, rb_tree_tag,tree_order_statistics_node_update>;
  53. const int N = 60;
  54. int r,c;
  55. char a[N][N];
  56. int dx[] = {1,0,-1,0},
  57. 	dy[] = {0,1,0,-1};
  58.  
  59. namespace hungeazy {
  60.  
  61. 	int d[20][20],dist[N][N],pos[N][N],dp[16][MASK(16)],len;
  62. 	bool ok[N][N],visited[N][N];
  63. 	vii vec;
  64.  
  65. 	bool check(int x, int y)  {
  66. 		return (x >= 1 and x <= r and y >= 1 and y <= c);
  67. 	}
  68.  
  69. 	void BFS(int p)
  70. 	{
  71. 		FOR(i,0,len-1) d[p][i] = oo;
  72. 		FOR(i,1,r)
  73. 			FOR(j,1,c) 
  74. 			{
  75. 				visited[i][j] = false;
  76. 				dist[i][j] = oo;
  77. 			}
  78. 		d[p][p] = 0;
  79. 		dist[vec[p].fi][vec[p].se] = 0;
  80. 		visited[vec[p].fi][vec[p].se] = true;
  81. 		deque<pair<int,ii>> q;
  82. 		q.pb({p,vec[p]});
  83. 		while (!q.empty())
  84. 		{
  85. 			int cur = q.front().fi;
  86. 			auto [u,v] = q.front().se;
  87. 			q.pop_front();
  88. 			FOR(s,0,3)
  89. 			{
  90. 				int x = dx[s]+u, y = dy[s]+v, newCur = cur;
  91. 				if (!check(x,y) or a[x][y] == '.') continue;
  92. 				if (a[x][y] == 'S')
  93. 				{
  94. 					if (minimize(dist[x][y],dist[u][v]+1) and !visited[x][y])	
  95. 					{
  96. 						visited[x][y] = true;
  97. 						q.pb({cur,{x,y}});
  98. 					}
  99. 				}
  100. 				else  
  101. 				{
  102. 					if (minimize(dist[x][y],dist[u][v]) and !visited[x][y])
  103. 					{
  104. 						if (ok[x][y]) 
  105. 						{
  106. 							int vt = pos[x][y];
  107. 							minimize(d[p][vt],d[p][cur]+dist[x][y]);
  108. 							newCur = vt;
  109. 						}
  110. 						visited[x][y] = true;
  111. 						q.push_front({newCur,{x,y}});
  112. 					}
  113. 				}
  114. 			}
  115. 		}
  116. 	}
  117.  
  118. 	void solve(void)
  119. 	{	
  120. 		FOR(i,1,r)
  121. 			FOR(j,1,c)	
  122. 				if (a[i][j] == 'X') 
  123. 				{
  124. 					vec.pb({i,j});
  125. 					ok[i][j] = true;
  126. 				}
  127. 		if (vec.empty())
  128. 		{
  129. 			cout << 0;
  130. 			return;
  131. 		}
  132. 		len = sz(vec);
  133. 		FOR(i,0,len-1) pos[vec[i].fi][vec[i].se] = i;
  134. 		FOR(i,0,len-1) BFS(i);
  135. 		fill(dp,0x3f);
  136. 		int INF = dp[0][0];
  137. 		FOR(i,0,len-1) dp[i][MASK(i)] = 0;
  138. 		FOR(mask,1,MASK(len)-1)
  139. 			FOR(i,0,len-1)
  140. 				if (BIT(mask,i) and dp[i][mask] != INF)
  141. 				{
  142. 					FOR(j,0,len-1)
  143. 						if (!BIT(mask,j))
  144. 							minimize(dp[j][SET_ON(mask,j)],dp[i][mask]+d[i][j]);
  145. 				} 
  146. 		int ans = oo;
  147. 		FOR(i,0,len-1) minimize(ans,dp[i][MASK(len)-1]);
  148. 		cout << ans;
  149. 	}
  150.  
  151. }
  152.  
  153. bool M2;
  154. signed main()
  155. {
  156.     fast;
  157.     if (fopen(name".inp","r"))
  158.     {
  159.     	freopen(name".inp","r",stdin);
  160.     	freopen(name".out","w",stdout);
  161.     }
  162.     cin >> r >> c;
  163.     FOR(i,1,r)
  164.     	FOR(j,1,c) cin >> a[i][j];
  165.     hungeazy::solve();
  166.     time();
  167.     memory();
  168.     return 0;
  169. }
  170. // ██░ ██  █    ██  ███▄    █   ▄████
  171. //▓██░ ██▒ ██  ▓██▒ ██ ▀█   █  ██▒ ▀█▒
  172. //▒██▀▀██░▓██  ▒██░▓██  ▀█ ██▒▒██░▄▄▄░
  173. //░▓█ ░██ ▓▓█  ░██░▓██▒  ▐▌██▒░▓█  ██▓
  174. //░▓█▒░██▓▒▒█████▓ ▒██░   ▓██░░▒▓███▀▒
  175. // ▒ ░░▒░▒░▒▓▒ ▒ ▒ ░ ▒░   ▒ ▒  ░▒   ▒
  176. // ▒ ░▒░ ░░░▒░ ░ ░ ░ ░░   ░ ▒░  ░   ░
  177. // ░  ░░ ░ ░░░ ░ ░    ░   ░ ░ ░ ░   ░
  178. // ░  ░  ░   ░              ░       ░
Success #stdin #stdout #stderr 0.01s 5288KB
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-------------Time:7.574ms.
8.06839 MB
https://ideone.com/PhJVD8
language:
C++14 (gcc 8.3)
created:
6 days ago
visibility:
public

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