def validate$\_$symbol$\_$counts$($fleet$\_$grid: list$[$list$[$str$]],$

ship$\_$symbols: list$[$str$],$

ship$\_$sizes: list$[$int$])->$ bool:

$""$ "Return True if and only if fleet$\_$grid contains each ship symbol in

ship$\_$symbols the correct corresponding number of times from ship$\_$sizes,

and nothing else except for the EMPTY character.

ship$\_$symbols and ship$\_$sizes are parallel lists.

Note: This function does not consider whether ship symbols are positioned

in an appropriate manner to form a complete ship. It simply validates the

symbol counts.

Preconditions:

$i=0$def $validat{e}_{s}ymbo{l}_c$ounts$(flee{t}_g$rid: list$[list[str]],$

$shi{p}_s$ymbols: list$[str],$

$shi{p}_s$izes: list$[int])$ bool:

$"""Return$ True $if$ and only $ifflee{t}_g$rid contains each ship symbol $in$

$shi{p}_s$ymbols the correct corresponding number $of$ times from $shi{p}_s$izes,

and nothing else except for the EMPTY character.

$shi{p}_s$ymbols and $shi{p}_s$izes are parallel lists.

Note: This function does not consider whether ship symbols are positioned

$inan$ appropriate manner $to$ form a complete ship. $It$ simply validates the

symbol counts.

Preconditions:

$-0$ len$(flee{t}_g$rid$)$

$-$ len$(flee{t}_g$rid$[i])==$ len$(flee{t}_g$rid$)$

for each value $ofiin$ range$(len(flee{t}_g$rid$))$

$-$ len$(shi{p}_s$ymbols$)==$ len$(shi{p}_s$izes$)$ and $0$ len$(shi{p}_s$ymbols$)$

$-$ len$(shi{p}_s$ymbols$[i])==1$

for each value $ofiin$ range$(len(shi{p}_s$ymbols$))$

$-1$ len$(shi{p}_s$izes$[i])$

for each value $ofiin$ range$(len(shi{p}_s$izes$))$

$>>>$ grid $=[[EMPTY,\text{'}b\text{'},$ EMPTY$],[EMPTY,\text{'}b\text{'},$ EMPTY$],[\text{'}a\text{'},\text{'}a\text{'},\text{'}a\text{'}]]$

$>>>$ ships $=[\text{'}a\text{'},\text{'}b\text{'}]$

$>>>$ sizes $=[3,2]$

$>>>validat{e}_{s}ymbo{l}_c$ounts$(grid,$ ships, sizes$)$

True

$>>>$ grid $=[[\text{'}b\text{'},$ EMPTY, EMPTY$],[EMPTY,\text{'}b\text{'},\text{'}a\text{'}],[\text{'}a\text{'},\text{'}a\text{'},$ EMPTY$]]$

$>>>$ ships $=[\text{'}a\text{'},\text{'}b\text{'}]$

$>>>$ sizes $=[3,2]$

$>>>validat{e}_{s}ymbo{l}_c$ounts$(grid,$ ships, sizes$)$

True

$>>>$ grid $=[[\text{'}d\text{'},\text{'}a\text{'},\text{'}n\text{'}],[EMPTY,\text{'}i\text{'},\text{'}s\text{'}],[\text{'}f\text{'},\text{'}i\text{'},\text{'}t\text{'}]]$

$>>>$ ships $=[\text{'}a\text{'},\text{'}d\text{'},\text{'}f\text{'},\text{'}i\text{'},\text{'}n\text{'}]$

$>>>$ sizes $=[1,1,1,2,1]$

$>>>validat{e}_{s}ymbo{l}_c$ounts$(grid,$ ships, sizes$)$

False

$"""$