[leetcode]29. Divide Two Integers@Java解题报告

https://leetcode.com/problems/divide-two-integers/description/

Divide two integers without using multiplication, division and mod operator.

If it is overflow, return MAX_INT.

package go.jacob.day730;public class Demo2 {public int divide(int dividend, int divisor) {// 结果的符号int flag = 1;if ((dividend > 0 && divisor < 0) || (dividend < 0 && divisor > 0))flag = -1;//把除数和被除数转化为正数进行判断long ldividend = Math.abs((long) dividend);long ldivisor = Math.abs((long) divisor);if (ldividend == 0 || ldividend < ldivisor)return 0;if (ldivisor == 0)return Integer.MAX_VALUE;long res = solve(ldividend, ldivisor);int ans;//如果结果溢出，根据符号输出相应的值if (res > Integer.MAX_VALUE)ans = flag == 1 ? Integer.MAX_VALUE : Integer.MIN_VALUE;elseans = (int) (flag * res);return ans;}private long solve(long ldividend, long ldivisor) {if(ldividend<ldivisor)return 0;long res = 1;long sum = ldivisor;//为防止进行多次重复的计算，每一次循环除数*2while (sum + sum <= ldividend) {sum += sum;res += res;}return res + solve(ldividend - sum, ldivisor);}}