Find integers a, b & c - of course, if you can!

Find integers a, b and c such that :-

987654321a + 123456789b + c = (a + b + c)³

There are (at least) 3 solutions with a and b non-zero.

Replies

  • Differential
    Differential
    Can "C" be more than 1 digit number ?
  • Kaustubh Katdare
    Kaustubh Katdare
    I don't know, seriously.
  • nishank_eureka
    nishank_eureka
    put three for loops each iterating from 0 to 9 and check the condition above.
    Manually i dont think i can find it.

    Here is the programme.
    Disclaimer: The synatx may not be proper.

    for(a=0;a<=9;a++)
    {
    for(b=0;b<=9;b++)
    {
    for(c=0;c<=9;c++)
    {
    int a1 = 9876543210 + a;
    int a2 =1234567890 + b;
    int cube = Math.pow((a+b+c),3);
    int Sum = a1 + a2;
    int result = a1.compareTo(a2);
    if (result ==0)
    {
    syso(a,b,c);
    }else
    continue;
    }
    }
    }
  • electron1212
    electron1212
    450 * 987654321 + 4500 * 123456789 + 5050 = (450+4500+5050) ^ 3 = 1000000000000

    7350 * 987654321 + 6000 * 123456789 + 6650 = (7350+6000+6650) ^ 3 = 8000000000000

    but what is the trick ???😕
  • Fazil
    Fazil
    My Program found 4 results. First three found with in 1 Min 48 seconds. Total scan took 7 Min 19 seconds.

    Result:
    {0, 0, 1} - 0 Sec
    {450, 4500, 5050} - 6 Sec
    {7350, 6000, 6650} - 1 Min 48 Sec
    {27150, 1500, 1350} - 6 Min 24 Sec

    Program:
    void main()
    {
    unsigned long double LHS, RHS, Duration;
    int a, b, c, Left, Right;
    time_t Start, Stop;

    time( &Start );
    for( a = 0; a < 31427; a++ )
    {
    for( b = 0; b < 31427; b++ )
    {
    Left = 0;
    Right = 31428;

    while( Left < ( Right - 1 ))
    {
    c = ( Left + Right ) / 2;

    LHS = unsigned long double(a) * 987654321;
    LHS += unsigned long double(b) * 123456789;
    LHS += unsigned long double(c);

    RHS = unsigned long double( a + b + c );
    RHS = RHS * RHS * RHS;

    if( LHS == RHS )
    {
    printf("\n\n987654321*%d + 123456789*%d + %d = %.0Lf\n", a, b, c, LHS);
    printf("(%d + %d + %d)^3 = %.0Lf\n", a, b, c, RHS);
    printf("987654321*%d + 123456789*%d + %d = (%d + %d + %d)^3\n\n", a, b, c, a, b, c);
    break;
    }
    if( LHS < RHS )
    {
    Right = c;
    }
    else
    {
    Left = c;
    }
    }
    }
    time( &Stop );
    Duration = difftime( Stop, Start );
    int Seconds = (int)fmod( Duration, 60 );
    int Minutes = (int)fmod( floor(Duration / 60), 60 );
    int Hours = int(Duration / 3600);

    printf("\rCompleted:%0.1Lf%%", (a * 100.) / 31427);
    printf("\tElapsed Time:%02d:%02d:%02d", Hours, Minutes, Seconds);
    }
    }

    Output:
    987654321*0 + 123456789*0 + 1 = 1
    (0 + 0 + 1)^3 = 1
    987654321*0 + 123456789*0 + 1 = (0 + 0 + 1)^3

    Completed:1.4% Elapsed Time:00:00:06

    987654321*450 + 123456789*4500 + 5050 = 1000000000000
    (450 + 4500 + 5050)^3 = 1000000000000
    987654321*450 + 123456789*4500 + 5050 = (450 + 4500 + 5050)^3

    Completed:23.4% Elapsed Time:00:01:48

    987654321*7350 + 123456789*6000 + 6650 = 8000000000000
    (7350 + 6000 + 6650)^3 = 8000000000000
    987654321*7350 + 123456789*6000 + 6650 = (7350 + 6000 + 6650)^3

    Completed:86.4% Elapsed Time:00:06:24

    987654321*27150 + 123456789*1500 + 1350 = 27000000000000
    (27150 + 1500 + 1350)^3 = 27000000000000
    987654321*27150 + 123456789*1500 + 1350 = (27150 + 1500 + 1350)^3

    Completed:100.0% Elapsed Time:00:07:19
  • Saandeep Sreerambatla
    Saandeep Sreerambatla
    Superb Solution Fazil.

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