The 11th Blue Bridge Cup-A House Plate Making

House number making

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from Lanqiao 11 - A

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Solving code:

#include<iostream>
using namespace std;
int all;
void solve(int x){
    
          //统计每个数字包含2的个数
    while(x){
    
    
        if(x % 10 == 2)
            ++all;
        x /= 10;
    }
}
int main(){
    
    
    for(int i = 1;i <= 2020;++i)
        solve(i);
    cout<<all;
    return 0;
}