[sword finger offer] interview question 46: translating numbers into strings - dynamic programming

Method 1 ： Dynamic programming

By establishing the transfer equation f(i) = f(i-1) + g(i,i-1)*f(i-2)
If the first two numbers are 10-25 Between , be g(i,i-1) by 1, Otherwise 0

class Solution {
    
public:
    int translateNum(int num) {
    
        string nums = to_string(num);
        vector<int> dp( nums.size() + 1, 0);
        dp[0] = 1;
        dp[1] = 1;
        for ( int i = 2; i <= nums.size(); i++)
        {
    
            dp[i] += dp[i - 1];
            int temp = ( nums[i - 2] - '0' ) * 10 + ( nums[ i -1 ] - '0');
            if(  temp >=10 && temp <= 25 )
                dp[i] += dp[i - 2];
        }
        return dp[nums.size()];
    }
};