49 lines
1.5 KiB
C++
49 lines
1.5 KiB
C++
// Source : https://leetcode.com/problems/add-strings/
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// Author : Hao Chen
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// Date : 2016-11-12
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/***************************************************************************************
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*
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* Given two non-negative numbers num1 and num2 represented as string, return the sum
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* of num1 and num2.
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*
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* Note:
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*
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* The length of both num1 and num2 is
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* Both num1 and num2 contains only digits 0-9.
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* Both num1 and num2 does not contain any leading zero.
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* You must not use any built-in BigInteger library or convert the inputs to integer
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* directly.
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***************************************************************************************/
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class Solution {
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public:
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string addStrings(string num1, string num2) {
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string& longstr = ( num1.size() >= num2.size() ? num1 : num2 );
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string& shortstr = ( num1.size() < num2.size() ? num1 : num2 );
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int longlen = longstr.size();
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int shortlen = shortstr.size();
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char carry = 0;
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int i, j;
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string result;
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for (i = longlen-1, j=shortlen-1; i>=0; i--, j--) {
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int add = 0;
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if (j>=0) {
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add = longstr[i] + shortstr[j] - 2 * '0' + carry;
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}else{
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add = longstr[i] - '0' + carry;
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}
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carry = add/10;
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result = char('0' + add % 10) + result;
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}
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if (carry) {
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result = '1' + result;
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}
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return result;
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}
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};
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