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79 lines
2.5 KiB
Java
79 lines
2.5 KiB
Java
// Given two integers dividend and divisor, divide two integers without using multiplication, division, and mod operator.
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//
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// The integer division should truncate toward zero, which means losing its fractional part. For example, 8.345 would be truncated to 8,
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// and -2.7335 would be truncated to -2.
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// My method used Long Division, here is the source "https://en.wikipedia.org/wiki/Long_division"
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package com.thealgorithms.maths;
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public class LongDivision {
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public static int divide(int dividend, int divisor) {
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long new_dividend_1 = dividend;
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long new_divisor_1 = divisor;
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if (dividend < 0) {
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new_dividend_1 = new_dividend_1 * -1;
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}
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if (divisor < 0) {
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new_divisor_1 = new_divisor_1 * -1;
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}
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if (dividend == 0 || new_dividend_1 < new_divisor_1) {
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return 0;
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}
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StringBuilder answer = new StringBuilder();
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String dividend_string = "" + new_dividend_1;
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int last_index = 0;
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String remainder = "";
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for (int i = 0; i < dividend_string.length(); i++) {
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String part_v1 = remainder + "" + dividend_string.substring(last_index, i + 1);
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long part_1 = Long.parseLong(part_v1);
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if (part_1 > new_divisor_1) {
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int quotient = 0;
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while (part_1 >= new_divisor_1) {
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part_1 = part_1 - new_divisor_1;
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quotient++;
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}
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answer.append(quotient);
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} else if (part_1 == new_divisor_1) {
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int quotient = 0;
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while (part_1 >= new_divisor_1) {
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part_1 = part_1 - new_divisor_1;
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quotient++;
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}
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answer.append(quotient);
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} else if (part_1 == 0) {
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answer.append(0);
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} else if (part_1 < new_divisor_1) {
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answer.append(0);
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}
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if (!(part_1 == 0)) {
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remainder = String.valueOf(part_1);
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}else{
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remainder = "";
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}
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last_index++;
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}
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if ((dividend < 0 && divisor > 0) || (dividend > 0 && divisor < 0)) {
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try {
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return Integer.parseInt(answer.toString()) * (-1);
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} catch (NumberFormatException e) {
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return -2147483648;
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}
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}
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try {
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return Integer.parseInt(answer.toString());
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} catch (NumberFormatException e) {
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return 2147483647;
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}
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}
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}
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