这三种冒泡排序的区别

Question

for ( i = 0 ; i < n - 1 ;  i ++){

        for ( j = i + 1 ; j < n ; j ++){

                if ( a[ i ] > a[ j ])

                        swap( a[ i ] , a[ j ]);

        }    

}

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for ( i = 0 ; i < n - 1 ;  i ++){

        for ( j = 0 ; j < n - i - 1 ; j ++){

                if ( a[ j ] > a[ j + 1 ])

                        swap( a[ j ] , a[ j + 1 ]);

        }    

}

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for ( i = 0 ; i < n - 1 ;  i ++){

        for ( j = n - 1 ; j > i ; -- j ){

                if ( a[ i ] > a[ j ])

                        swap( a[ i ] , a[ j ]);

        }    

}

Answer 1

哪一种最优？