1. 问题描述

Given a non-negative number represented as an array of digits, plus one to the number.

The digits are stored such that the most significant digit is at the head of the list.

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Tags: Array Math

Similar Problems: (M) Multiply Strings (E) Add Binary

2. 解答思路

3. 代码

1 #include 
     
       2 using namespace std; 3 class Solution { 4 public: 5     vector
      
        plusOne_method_1(vector
       
        & digits) { 6         if (digits.empty()) 7         { 8             digits.push_back(1); 9             return digits;10         }11         return puls(digits, digits.size()-1, 1);12     }13     vector
        
          plusOne_method_2(vector
         
          & digits) {14         if (digits.empty())15         {16             digits.push_back(1);17             return digits;18         }19         int nTakeOver = 1;20         int i;21         for (i=digits.size()-1; i>=0; i--)22         {23             int sum = digits[i] + nTakeOver;24             digits[i] = sum%10;25             nTakeOver = sum/10;26             if (0 == nTakeOver)27             {28                 return digits;29             }30         }31         if (1 == nTakeOver)32         {33             digits.insert(digits.begin(), 1);34         }35         return digits;36     }37 private:38     vector
          
            puls(vector
           
            & digits, int idx, int nTakeOver = 0)39 {40 int sum = digits[idx] + nTakeOver;41 digits[idx] = sum%10;42 nTakeOver = sum/10;43 if (0 == nTakeOver)44 {45 return digits;46 }47 if (0 == idx)48 {49 digits.insert(digits.begin(), 1);50 return digits;51 }52 return puls(digits, idx-1, 1);53 }54 };