init: repo

open_set/40_percolation.pas

@@ -0,0 +1,80 @@
+program main;
+var 
+arr: array[0..109] of integer;
+n: integer;
+m, a, b, k, loc, i: integer;
+flag: boolean;
+
+procedure init(n: integer);
+var i: integer;
+begin
+  for i := 1 to n * n + 1 do
+    arr[i] := -1;
+end;
+
+function findfa(a: integer):integer;
+begin
+  if arr[a] = a then
+    findfa := a
+  else
+  begin
+    arr[a] := findfa(arr[a]);
+    findfa := arr[a];
+  end;
+end;
+
+procedure mmerge(a, b: integer);
+var m, n: integer;
+begin
+  m := findfa(a);
+  n := findfa(b);
+  if m <> n then
+    arr[m] := n;
+end;
+
+begin
+  n := 4;
+  m := 10;
+  flag := false;
+  init(n);
+  k := n * n + 1;
+
+  for i := 0 to m - 1 do
+  begin
+    read(a);
+    read(b);
+    if flag = false then
+    begin
+      loc := n * (a - 1) + b;
+      arr[loc] := loc;
+      if a = 1 then
+      begin
+        arr[0] := 0;
+        mmerge(loc, 0);
+      end;
+      if a = n then
+      begin
+        arr[k] := k;
+        mmerge(loc, k);
+      end;
+
+      if (b < n) and (arr[loc + 1] <> -1) then
+        mmerge(loc, loc + 1);
+      if (b > 1) and (arr[loc - 1] <> -1) then
+        mmerge(loc, loc - 1);
+      if (a < n) and (arr[loc + n] <> -1) then
+        mmerge(loc, loc + n);
+      if (a > 1) and (arr[loc - n] <> -1) then
+        mmerge(loc, loc - n);
+
+      if (arr[0] <> -1) and (arr[k] <> -1) and (findfa(0) = findfa(k)) then
+      begin
+        flag := true;
+        write(i + 1);
+      end;
+    end;
+  end;
+
+  if flag = false then
+    write(-1);
+end.