LeeCode_MultiplyStrings
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经过昨天一天,还有今天的学习,终于是把第一个程序给搞出来,虽然是借鉴他人的,但是还是收获颇多。现在把
这个程序的问题,和解决方案在下面贴出:
MultiplyStrings
Given two numbers represented as strings, return multiplication of the numbers as a string.
Note: The numbers can be arbitrarily large and are non-negative.
给定用字符串表示的两个数字,计算其乘积:public class MultiplyStrings {//这种算法是模拟了正常的乘积运算解出答案。
<span style="white-space:pre"></span>//原始解法中问号部分,我认为是不需要的,不太理解是什么意思,
<span style="white-space:pre"></span>//我在Leecode中测试是可以通过的。public static void main(String[] args) { String a1 = "12888"; String b1 = "13131555";String s = multiply(a1, b1);System.out.println("s =" + s); } public static String multiply(String num1, String num2) { StringBuilder s1 = new StringBuilder(num1).reverse(); StringBuilder s2 = new StringBuilder(num2).reverse(); int l1 = s1.length(); int l2 = s2.length(); int[] result = new int[l1 + l2 - 1]; for(int i = 0; i < l1; i++){ for(int j = 0; j < l2; j++){ result[i+j] += (s1.charAt(i) - '0') * (s2.charAt(j) - '0'); } } //System.out.println(Arrays.toString(result)); StringBuilder s = new StringBuilder(); int carry = 0; for(int i = 0; i < result.length; i++){ int currDigit = (result[i] + carry) % 10; carry = (result[i]+carry)/10; s.insert(0, currDigit); System.out.println(s); } if(carry!=0){ s.insert(0, carry); }/*??????????????????????????????????????????????????????? int i = 0; while( i < s.length() && s.charAt(i) == '0'){ i++; } if(i == s.length() ) s.delete(0,i-1); else s.delete(0, i);*/ return s.toString(); }}
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