Java Number Sum sumFirstNDivisibleByM(long n, long m)

Description

sum First N Divisible By M

License

Apache License

Declaration

public static long sumFirstNDivisibleByM(long n, long m) 

Method Source Code

//package com.java2s;
/**//from   ww w.  j  a  va2  s  .  c  o  m
 *
 * maer - Solutions to problems of Project Euler
 * Copyright (C) 2011, Sandeep Gupta
 * http://www.sangupta.com/projects/maer
 *
 * The file is licensed under the the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

public class Main {
    public static long sumFirstNDivisibleByM(long n, long m) {
        return sumFirstNDivisibleByM(n, m, true);
    }

    public static long sumFirstNDivisibleByM(long n, long m, boolean includeN) {
        if (!includeN) {
            n -= 1;
        }
        return m * sumFirstN(n / m);
    }

    public static long sumFirstN(long n) {
        return (n * (n + 1)) / 2;
    }
}

Related

1. sumDigits(String number)
2. sumDivisors(int n)
3. sumError(long samples, long count, double m2, double mean)
4. sumFirstIntegers(final long i)
5. sumFirstN(long n)
6. sumFromNtoM(int n, int m)
7. sumHadOverflow(long a, long b, long sum)
8. sumHash(int hash, String element)
9. sumHash(int leftHash, int rightHash)