class Solution {public:int NumberOf1Between1AndN_Solution(int n){if(n==0) return 0;vector<int> number;while(n!=0) number.push_back(n),n/=10;int res=0;for(int i=number.size()-1;i>=0;i--){int left=0,right=0,t=1;for(int j=number.size()-1;j>i;j--) left = left*10+number[j];for(int j=i-1;j>=0;j--) right = right*10 + number[j],t*=10;res+=left*t;if(number[i]==1) res += right + 1;else if(number[i]>1) res += t;}return res;}};