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uHan2
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| public static BigInteger karatsubaMultiply(BigInteger x, BigInteger y) { | ||
| int n = Math.max(x.bitLength(), y.bitLength()); | ||
| if (n <= 3) { | ||
| return x.multiply(y); | ||
| } | ||
| int m = (n + 1) / 2; | ||
| // Split x and y into high and low parts | ||
| BigInteger xHigh = x.shiftRight(m); | ||
| BigInteger xLow = x.subtract(xHigh.shiftLeft(m)); | ||
| BigInteger yHigh = y.shiftRight(m); | ||
| BigInteger yLow = y.subtract(yHigh.shiftLeft(m)); | ||
| // Recursively compute sub-products | ||
| BigInteger a = karatsubaMultiply(xHigh, yHigh); | ||
| BigInteger b = karatsubaMultiply(xLow, yLow); | ||
| BigInteger c = karatsubaMultiply(xHigh.add(xLow), yHigh.add(yLow)).subtract(a).subtract(b); | ||
| // Combine sub-products to get the final result | ||
| return a.shiftLeft(2 * m).add(c.shiftLeft(m)).add(b); | ||
| } |
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wow impressive. i just multiple two integer, but you implemented Karatsuba algorythm literally. i learned a lot by your code. thanks.
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