14 deleted 1 character in body
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Lua, 146 142 108 162 159 149 144 135 132 118 118113 bytes

z,q,s=0,0,io.read()for i in s:gmatch('gmatch'.')do'do t=i-z if 2==math.abs(t)or t==q then return 1<0 endreturn''end q=-t z=i end return 2>1

Lua, 146 142 108 162 159 149 144 135 132 118 bytes

z,q,s=0,0,io.read()for i in s:gmatch('.')do t=i-z if 2==math.abs(t)or t==q then return 1<0 end q=-t z=i end return 2>1

Lua, 146 142 108 162 159 149 144 135 132 118 113 bytes

z,q,s=0,0,io.read()for i in s:gmatch'.'do t=i-z if 2==math.abs(t)or t==q then return''end q=-t z=i end return 2>1
13 Typo
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Lua, 146 142 108 162 159 149 144 135 132 132118 bytes

z,q,s=0,0,io.read()for i in s:gmatch('.')do t=i-z if t then if 2==math.abs(t)or t==q then return 1<0 end q=-t end z=i end return 2>1

Lua, 146 142 108 162 159 149 144 135 132 bytes

z,q,s=0,0,io.read()for i in s:gmatch('.')do t=i-z if t then if 2==math.abs(t)or t==q then return 1<0 end q=-t end z=i end return 2>1

Lua, 146 142 108 162 159 149 144 135 132 118 bytes

z,q,s=0,0,io.read()for i in s:gmatch('.')do t=i-z if 2==math.abs(t)or t==q then return 1<0 end q=-t z=i end return 2>1
12 Typo
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z,q,s=0,0,io.read()for i in s:gmatch('.')do t=i-z if t then if 2==math.abs(t)or t==q then return 1>01<0 end q=-t end z=i end return 2>1
z,q,s=0,0,io.read()for i in s:gmatch('.')do t=i-z if t then if 2==math.abs(t)or t==q then return 1>0 end q=-t end z=i end return 2>1
z,q,s=0,0,io.read()for i in s:gmatch('.')do t=i-z if t then if 2==math.abs(t)or t==q then return 1<0 end q=-t end z=i end return 2>1
11 added 373 characters in body
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10 added 1187 characters in body
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9 Added reference for variable swapping
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8 All that editing and I forgot to add the updated code...
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7 deleted 13 characters in body
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6 added 165 characters in body
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5 ...
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4 deleted 216 characters in body
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3 deleted 2 characters in body
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2 Fixed code block (the second line needed to be indented) and fixed syntax highlighting setting
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1
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