First Non-Repeating Character

First Non-Repeating Character

Medium PHP PHP Strings 46 views
Explanation Complexity

Problem Statement

Print the first character that appears only once. If none, print -1.

Input Format

One line string s.

Output Format

One character or -1.

Example

aabbcddee
c

Constraints

|s|

Input / Output Format

Input Format
One line string s.
Output Format
One character or -1.
Constraints
|s|

Examples

Input:
aabbcddee
Output:
c

Example Solution (Public)

PHP
<?php
$inputText=rtrim(stream_get_contents(STDIN));
if($inputText==='') exit;
$freq=[];
for($i=0,$n=strlen($inputText);$i<$n;$i++){
  $ch=$inputText[$i];
  if(!isset($freq[$ch])) $freq[$ch]=0;
  $freq[$ch]++;
}
$ans='-1';
for($i=0,$n=strlen($inputText);$i<$n;$i++) if(($freq[$inputText[$i]] ?? 0)===1){ $ans=$inputText[$i]; break; }
echo $ans;
?>

Official Solution Code

<?php
$inputText=rtrim(stream_get_contents(STDIN));
if($inputText==='') exit;
$freq=[];
for($i=0,$n=strlen($inputText);$i<$n;$i++){
  $ch=$inputText[$i];
  if(!isset($freq[$ch])) $freq[$ch]=0;
  $freq[$ch]++;
}
$ans='-1';
for($i=0,$n=strlen($inputText);$i<$n;$i++) if(($freq[$inputText[$i]] ?? 0)===1){ $ans=$inputText[$i]; break; }
echo $ans;
?>
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