Check If N == M*2 in the array-CodePudding

I'm starting solving problem on leetcode, this problem didn't pass the test cases, this my try:

function checkIfExist($arr) {
    
    $i = 0;
    $j = 0;
    $n = count($arr);
    
    // loop over the array
    for($i; $i < $n; $i  ) {
        for($j; $j < $n; $j  ) {    
            // check if element of i and j not the same and N*2 = M
            if ($i != $j && $arr[$i] * 2 == $arr[$j]) {
                return true;
            }
        }
    }
    return false;
}

Can please explain to me where I did the error here?

CodePudding user response：

This should work, try this though (it's like one of the sort algorithms). That is weird because only difference is the initialization of the $i and $j

function checkIfExist($arr) {
    
    $n = count($arr);
    
    // loop over the array
    for($i = 0; $i < $n - 1; $i  ) {
        for($j = $i   1; $j < $n; $j  ) {    
            // check if element of i and j not the same and N*2 = M
            if ($i != $j && $arr[$i] * 2 == $arr[$j]) {
                return true;
            }
        }
    }
    return false;
}

CodePudding user response：

The initializing of $j and $i pointer inside the for-loop done the work

 function checkIfExist($arr) {
    
        $n = count($arr);
    
        // loop over the array
        for($i = 0; $i < $n; $i  ) {
            for($j = 0; $j < $n; $j  ) {    
                // check if element of i and j not the same and N*2 = M
                if ($i != $j && $arr[$i] * 2 == $arr[$j]) {
                    return true;
                }
            }
        }
        return false;
    }