From 87813ae8987016f7fed9907c6fe007bd700a58d4 Mon Sep 17 00:00:00 2001 From: Looly Date: Sun, 7 Mar 2021 11:39:03 +0800 Subject: [PATCH] add method --- CHANGELOG.md | 3 +- .../java/cn/hutool/core/util/NumberUtil.java | 54 ++++++++++++++- .../cn/hutool/core/util/NumberUtilTest.java | 67 ++++++++++++------- 3 files changed, 98 insertions(+), 26 deletions(-) diff --git a/CHANGELOG.md b/CHANGELOG.md index 67ed84e2b..36780cfc4 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -3,7 +3,7 @@ ------------------------------------------------------------------------------------------------------------- -# 5.6.0 (2021-03-05) +# 5.6.0 (2021-03-07) ### 新特性 * 【poi 】 重要：不再兼容POI-3.x，增加兼容POI-5.x（issue#I35J6B@Gitee） @@ -12,6 +12,7 @@ * 【crypto 】 增加PBKDF2（issue#1416@Github） * 【core 】 增加FuncKeyMap（issue#1402@Github） * 【core 】 增加StrMatcher（issue#1379@Github） +* 【core 】 NumberUtil增加factorial针对BigInterger方法（issue#1379@Github） ### Bug修复 * 【socket 】 修复Client创建失败资源未释放问题。 diff --git a/hutool-core/src/main/java/cn/hutool/core/util/NumberUtil.java b/hutool-core/src/main/java/cn/hutool/core/util/NumberUtil.java index 6d4698c6c..de890ec7e 100644 --- a/hutool-core/src/main/java/cn/hutool/core/util/NumberUtil.java +++ b/hutool-core/src/main/java/cn/hutool/core/util/NumberUtil.java @@ -1428,10 +1428,62 @@ public class NumberUtil { // ------------------------------------------------------------------------------------------- others + /** + * 计算阶乘 + *

+ * n! = n * (n-1) * ... * 2 * 1 + *

+ * + * @param n 阶乘起始 + * @return 结果 + * @since 5.6.0 + */ + public static BigInteger factorial(BigInteger n) { + if(n.equals(BigInteger.ZERO)){ + return BigInteger.ONE; + } + return factorial(n, BigInteger.ZERO); + } + /** * 计算范围阶乘 *

- * factorial(start, end) = start * (start - 1) * ... * (end - 1) + * factorial(start, end) = start * (start - 1) * ... * (end + 1) + *

+ * + * @param start 阶乘起始（包含） + * @param end 阶乘结束，必须小于起始（不包括） + * @return 结果 + * @since 5.6.0 + */ + public static BigInteger factorial(BigInteger start, BigInteger end) { + Assert.notNull(start, "Factorial start must be not null!"); + Assert.notNull(end, "Factorial end must be not null!"); + if(start.compareTo(BigInteger.ZERO) < 0 || end.compareTo(BigInteger.ZERO) < 0){ + throw new IllegalArgumentException(StrUtil.format("Factorial start and end both must be > 0, but got start={}, end={}", start, end)); + } + + if (start.equals(BigInteger.ZERO)){ + start = BigInteger.ONE; + } + + if(end.compareTo(BigInteger.ONE) < 0){ + end = BigInteger.ONE; + } + + BigInteger result = start; + end = end.add(BigInteger.ONE); + while(start.compareTo(end) > 0) { + start = start.subtract(BigInteger.ONE); + result = result.multiply(start); + } + return result; + } + + /** + * 计算范围阶乘 + *

+ * factorial(start, end) = start * (start - 1) * ... * (end + 1) *

* * @param start 阶乘起始（包含） diff --git a/hutool-core/src/test/java/cn/hutool/core/util/NumberUtilTest.java b/hutool-core/src/test/java/cn/hutool/core/util/NumberUtilTest.java index a6546efcd..116b75ddc 100644 --- a/hutool-core/src/test/java/cn/hutool/core/util/NumberUtilTest.java +++ b/hutool-core/src/test/java/cn/hutool/core/util/NumberUtilTest.java @@ -5,17 +5,18 @@ import org.junit.Assert; import org.junit.Test; import java.math.BigDecimal; +import java.math.BigInteger; import java.math.RoundingMode; import java.util.Set; /** * {@link NumberUtil} 单元测试类 - * + * * @author Looly * */ public class NumberUtilTest { - + @Test public void addTest() { Float a = 3.15f; @@ -23,7 +24,7 @@ public class NumberUtilTest { double result = NumberUtil.add(a, b).doubleValue(); Assert.assertEquals(7.37, result, 2); } - + @Test public void addTest2() { double a = 3.15f; @@ -31,7 +32,7 @@ public class NumberUtilTest { double result = NumberUtil.add(a, b); Assert.assertEquals(7.37, result, 2); } - + @Test public void addTest3() { float a = 3.15f; @@ -39,13 +40,13 @@ public class NumberUtilTest { double result = NumberUtil.add(a, b, a, b).doubleValue(); Assert.assertEquals(14.74, result, 2); } - + @Test public void addTest4() { BigDecimal result = NumberUtil.add(new BigDecimal("133"), new BigDecimal("331")); Assert.assertEquals(new BigDecimal("464"), result); } - + @Test public void isIntegerTest() { Assert.assertTrue(NumberUtil.isInteger("-12")); @@ -54,7 +55,7 @@ public class NumberUtilTest { Assert.assertTrue(NumberUtil.isInteger("0")); Assert.assertFalse(NumberUtil.isInteger("23.4")); } - + @Test public void isLongTest() { Assert.assertTrue(NumberUtil.isLong("-12")); @@ -63,7 +64,7 @@ public class NumberUtilTest { Assert.assertTrue(NumberUtil.isLong("0")); Assert.assertFalse(NumberUtil.isLong("23.4")); } - + @Test public void isNumberTest() { Assert.assertTrue(NumberUtil.isNumber("28.55")); @@ -78,7 +79,7 @@ public class NumberUtilTest { double result = NumberUtil.div(0, 1); Assert.assertEquals(0.0, result, 0); } - + @Test public void roundTest() { @@ -93,7 +94,7 @@ public class NumberUtilTest { String round4 = NumberUtil.roundStr("2.675", 2); Assert.assertEquals("2.68", round3); Assert.assertEquals("2.68", round4); - + // 四舍六入五成双 String round31 = NumberUtil.roundStr(4.245, 2, RoundingMode.HALF_EVEN); String round41 = NumberUtil.roundStr("4.2451", 2, RoundingMode.HALF_EVEN); @@ -105,7 +106,7 @@ public class NumberUtilTest { String round6 = NumberUtil.roundStr("2.6005", 2); Assert.assertEquals("2.60", round5); Assert.assertEquals("2.60", round6); - + // 补0 String round7 = NumberUtil.roundStr(2.600, 2); String round8 = NumberUtil.roundStr("2.600", 2); @@ -118,7 +119,7 @@ public class NumberUtilTest { String roundStr = NumberUtil.roundStr(2.647, 2); Assert.assertEquals(roundStr, "2.65"); } - + @Test public void roundHalfEvenTest() { String roundStr = NumberUtil.roundHalfEven(4.245, 2).toString(); @@ -129,7 +130,7 @@ public class NumberUtilTest { Assert.assertEquals(roundStr, "4.25"); roundStr = NumberUtil.roundHalfEven(4.2250, 2).toString(); Assert.assertEquals(roundStr, "4.22"); - + roundStr = NumberUtil.roundHalfEven(1.2050, 2).toString(); Assert.assertEquals(roundStr, "1.20"); roundStr = NumberUtil.roundHalfEven(1.2150, 2).toString(); @@ -159,14 +160,14 @@ public class NumberUtilTest { String format = NumberUtil.decimalFormat(",###", c); Assert.assertEquals("299,792,458", format); } - + @Test public void decimalFormatMoneyTest() { double c = 299792400.543534534; - + String format = NumberUtil.decimalFormatMoney(c); Assert.assertEquals("299,792,400.54", format); - + double value = 0.5; String money = NumberUtil.decimalFormatMoney(value); Assert.assertEquals("0.50", money); @@ -176,17 +177,17 @@ public class NumberUtilTest { public void equalsTest() { Assert.assertTrue(NumberUtil.equals(new BigDecimal("0.00"), BigDecimal.ZERO)); } - + @Test public void formatPercentTest() { String str = NumberUtil.formatPercent(0.33543545, 2); Assert.assertEquals("33.54%", str); } - + @Test public void toBigDecimalTest() { double a = 3.14; - + BigDecimal bigDecimal = NumberUtil.toBigDecimal(a); Assert.assertEquals("3.14", bigDecimal.toString()); @@ -208,7 +209,7 @@ public class NumberUtilTest { int min = NumberUtil.min(5,4,3,6,1); Assert.assertEquals(1, min); } - + @Test public void parseIntTest() { int number = NumberUtil.parseInt("0xFF"); @@ -258,7 +259,7 @@ public class NumberUtilTest { Number v2 = NumberUtil.parseNumber("1,482.00D"); Assert.assertEquals(1482L, v2); } - + @Test public void parseLongTest() { long number = NumberUtil.parseLong("0xFF"); @@ -303,18 +304,36 @@ public class NumberUtilTest { Assert.assertEquals(120, factorial); factorial = NumberUtil.factorial(5, 1); Assert.assertEquals(120, factorial); - + Assert.assertEquals(5, NumberUtil.factorial(5, 4)); Assert.assertEquals(2432902008176640000L, NumberUtil.factorial(20, 0)); } + @Test + public void factorialTest2(){ + long factorial = NumberUtil.factorial(new BigInteger("0")).longValue(); + Assert.assertEquals(1, factorial); + + Assert.assertEquals(1L, NumberUtil.factorial(new BigInteger("1")).longValue()); + Assert.assertEquals(1307674368000L, NumberUtil.factorial(new BigInteger("15")).longValue()); + Assert.assertEquals(2432902008176640000L, NumberUtil.factorial(20)); + + factorial = NumberUtil.factorial(new BigInteger("5"), new BigInteger("0")).longValue(); + Assert.assertEquals(120, factorial); + factorial = NumberUtil.factorial(new BigInteger("5"), BigInteger.ONE).longValue(); + Assert.assertEquals(120, factorial); + + Assert.assertEquals(5, NumberUtil.factorial(new BigInteger("5"), new BigInteger("4")).longValue()); + Assert.assertEquals(2432902008176640000L, NumberUtil.factorial(new BigInteger("20"), BigInteger.ZERO).longValue()); + } + @Test public void mulTest(){ final BigDecimal mul = NumberUtil.mul(new BigDecimal("10"), null); Assert.assertEquals(BigDecimal.ZERO, mul); } - - + + @Test public void isPowerOfTwoTest() { Assert.assertFalse(NumberUtil.isPowerOfTwo(-1));