题目的意思就是给你一个数字 n (1~81) 然后问你从 1~10^9 之中有多少个各位数字之和等于 n 的数字

我上去打表了而且速度还差不多 , 能在几十分钟内算出来所有答案 . 下面附上打表的方法

#include
     
      #include
      
       #include
       
        #include
        
         #include
         
          #include
          
           #include
           
            #include
            
             #include
             
              #include
              
               #include
               
                #include
                
                 #include
                 #include
                  
                   using namespace std;int main(){ int sum,q,j,m,result,flag; for(int n=1;n<=2;n++) { result=0; for(int i=1;i<=1000000000;i++) { j=i; flag=sum=0; while(j>0) { sum+=j%10; j=j/10; if(sum>n) break; } if(sum==n) result++; } printf("%d\n",result); }}

算出来结果之后就打表 .复制出来

1 #include
     
       2 #include
      
        3 #include
       
         4 #include
        
          5 #include
         
           6 #include
          
            7 #include
           
             8 #include
            
              9 #include
             
              10 #include
              
               11 #include
               
                12 #include
                
                 13 #include
                 14 #include
                  
                   15 using namespace std;16 int main()17 {18 int a[]={ 0,10,45,165,495,1287,3003,6435,12870,24310,43749,75501,125565,202005,315315,478731,708444,1023660,1446445,2001285,2714319,3612231,4720815,6063255,7658190,9517662,11645073,14033305,16663185,19502505,22505751,25614639,28759500,31861500,34835625,37594305,40051495,42126975,43750575,44865975,45433800,45433800,44865975,43750575,42126975,40051495,37594305,34835625,31861500,28759500,25614639,22505751,19502505,16663185,14033305,11645073,9517662,7658190,6063255,4720815,3612231,2714319,2001285,1446445,1023660,708444,478731,315315,202005,125565,75501,43749,24310,12870,6435,3003,1287,495,165,45,9,1};19 int n;20 while(scanf("%d",&n)!=EOF)21 {22 printf("%d\n",a[n]);23 }24 return 0;25 }