uses Crt;
const YN: array[boolean] of string[3] = ('No','Yes');
var
i: integer;
n: string;
b: boolean;
BEGIN
clrscr;
writeln('N = ?');
readln(n);
b:= true;
for i:= 2 to length(n) do
if n[1]<>n[i] then begin
b:= false;
break
end;
writeln(YN[b]);
readln
END.
Или так
var s:string;
f:boolean;
i:integer;
begin
readln(s);
i:=1;
f:=true;
while (i<=length(s)-1)and(f) do
if copy(s,i,1)<>copy(s,i+1,1) then f:=false;
inc(i)
if f then write('YES')
else write('NO');
end.
uses Crt;
const YN: array[boolean] of string[3] = ('No','Yes');
var
i: integer;
n: string;
b: boolean;
BEGIN
clrscr;
writeln('N = ?');
readln(n);
b:= true;
for i:= 2 to length(n) do
if n[1]<>n[i] then begin
b:= false;
break
end;
writeln(YN[b]);
readln
END.
Или так
var s:string;
f:boolean;
i:integer;
begin
readln(s);
i:=1;
f:=true;
while (i<=length(s)-1)and(f) do
begin
if copy(s,i,1)<>copy(s,i+1,1) then f:=false;
inc(i)
end;
if f then write('YES')
else write('NO');
readln
end.