60 lines
2.0 KiB
Java
60 lines
2.0 KiB
Java
package expression;
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import java.math.BigDecimal;
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import java.math.BigInteger;
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import java.util.List;
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/**
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* @author Doschennikov Nikita (me@fymio.us)
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*/
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public class Sqrt extends AbstractExpression {
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private final AbstractExpression operand;
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public Sqrt(AbstractExpression operand) {
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this.operand = operand;
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}
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private static int sqrtInt(int n) {
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if (n < 0) throw new ArithmeticException("sqrt of negative number: " + n);
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if (n == 0) return 0;
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// Binary search: floor(sqrt(n)), result <= 46340 (sqrt(MAX_INT) < 46341)
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int lo = 0, hi = 46340;
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while (lo < hi) {
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int mid = (lo + hi + 1) / 2;
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if (mid * mid <= n) {
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lo = mid;
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} else {
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hi = mid - 1;
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}
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}
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return lo;
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}
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@Override public int evaluate(int x) { return sqrtInt(operand.evaluate(x)); }
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@Override public int evaluate(int x, int y, int z) { return sqrtInt(operand.evaluate(x,y,z)); }
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@Override public int evaluate(List<Integer> vars) { return sqrtInt(operand.evaluate(vars)); }
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@Override public BigInteger evaluateBi(List<BigInteger> vars) { return operand.evaluateBi(vars).sqrt(); }
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@Override public BigDecimal evaluateBd(List<BigDecimal> vars) {
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throw new UnsupportedOperationException("sqrt not supported for BigDecimal");
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}
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@Override public String toString() { return "√(" + operand + ")"; }
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// @Override public String toMiniString() { return "√" + operand.toMiniString(); }
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@Override
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public String toMiniString() {
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if (operand instanceof AbstractBinaryOperation) {
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return "√(" + operand.toMiniString() + ")";
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}
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return "√" + operand.toMiniString();
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}
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@Override
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public boolean equals(Object obj) {
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if (this == obj) return true;
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if (!(obj instanceof Sqrt)) return false;
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return operand.equals(((Sqrt) obj).operand);
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}
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@Override public int hashCode() { return operand.hashCode() ^ 0x53515254; }
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} |