使用for循环来找到给定数字区间中数字的最小数字和

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英文:

Using for loop to find minimal sum of digits in given number interval

问题

  1. int minSum(int m, int n) {
  2.     for (int i = m; i <= n; i++) {
  3.         int sm = sum(i);
  4.         if (sm < min) min = sm;
  5.         if (min == sm) cnt++;
  6.     }
  7.     return cnt;
  8. }
英文:

So, I am doing a task that asks to find the amount of positive integers from interval [m, n] with minimum sum of digits.

I declared a function that computes the sum of digits, however I am having problems finding the amount of numbers. Below is the code I wrote for finding the minimum sum of digits and counting. I hope I made myself clear. I would appreciate if you could help me fix this code.

Input: 1 100
Output: 3

  1. int minSum(int m, int n){
  2.   
  3.     for (int i=m; i&lt;=n; i++){
  4.         int sm=sum(i);
  5.         if (sm&lt;min) min=sm;
  6.         if (min==sm)  cnt++;
  7.     }
  8.     return cnt;
  9. }

答案1

得分: 0

以下是翻译好的部分：

"For starters the variables min and cnt are not declared within the function. If they are a file scope variables then using file scope variables in the function is a bad idea."

首先，变量 min 和 cnt 在函数内未声明。如果它们是文件作用域变量，那么在函数中使用文件作用域变量是一个不好的主意。

"The function can look the following way. I assume that sum of digits can not be a negative number."

该函数可以如下所示。我假设数字的总和不会是负数。

"unsigned int minSum( int m, int n )
{
unsigned int cnt = 0;
int min = 0;

  1. if ( !( n &lt; m ) )
  2. {
  3.     do
  4.     {
  5.         int sm = sum( m );
  6.         if ( sm &lt; min ) 
  7.         {
  8.             min = sm;
  9.             cnt = 1;
  10.         }
  11.         else if ( !( min &lt; sm ) )
  12.         {
  13.             ++cnt;
  14.         }
  15.     } while ( m++ != n ); 
  16. }
  18. return cnt;

}"

"Pay attention to that the for loop in your original code

for (int i=m; i<=n; i++){

can invoke undefined behavior for example when n is equal to INT_MAX."

请注意，你原始代码中的 for 循环可能会在 n 等于 INT_MAX 时引发未定义行为。

英文:

For starters the variables min and cnt are not declared within the function. If they are a file scope variables then using file scope variables in the function is a bad idea.

The function can look the following way. I assume that sum of digits can not be a negative number.

  1. unsigned int minSum( int m, int n )
  2. {
  3.     unsigned int cnt = 0; 
  4.     int min = 0;
  6.     if ( !( n &lt; m ) )
  7.     {
  8.         do
  9.         {
  10.             int sm = sum( m );
  11.             if ( sm &lt; min ) 
  12.             {
  13.                 min = sm;
  14.                 cnt = 1;
  15.             }
  16.             else if ( !( min &lt; sm ) )
  17.             {
  18.                 ++cnt;
  19.             }
  20.         } while ( m++ != n ); 
  21.     }
  23.     return cnt;
  24. }

Pay attention to that the for loop in your original code

  1. for (int i=m; i&lt;=n; i++){

can invoke undefined behavior for example when n is equal to INT_MAX.

答案2

得分: 0

  1. int sum(int x)
  2. {
  3.     int result = 0;
  4.     while(x) 
  5.     {
  6.         result += abs(x % 10);
  7.         x /= 10;
  8.     }
  9.     return result;
  10. }
  12. size_t minSum(int m, int n){
  13.     int min = sum(m);
  14.     int sm;
  15.     size_t cnt = 0;
  17.     for (int i = m + 1; i <= n; i++)
  18.         if ((sm = sum(i)) < min) min = sm;
  20.     for (int i = m; i <= n; i++)
  21.         if (sum(i) == min) cnt++;
  23.     return cnt;
  24. }

Or less brute force:

  1. size_t minsum(int m, int n){
  2.     int min = sum(m);
  3.     int sm;
  4.     size_t cnt = 1;
  6.     for (int i = m + 1; i <= n; i++)
  7.     {
  8.         sm = sum(i);
  9.         if (sm < min) 
  10.         {
  11.             min = sm; 
  12.             cnt = 1;
  13.         }
  14.         else if(sm == min) cnt++;
  15.     }
  17.     return cnt;
  18. }
英文: 
  1. int sum(int x)
  2. {
  3.     int result = 0;
  4.     while(x) 
  5.     {
  6.         result += abs(x % 10);
  7.         x /= 10;
  8.     }
  9.     return result;
  10. }
  12. size_t minSum(int m, int n){
  13.     int min = sum(m);
  14.     int sm;
  15.     size_t cnt = 0;
  17.     for (int i = m + 1; i &lt;= n; i++)
  18.         if ((sm = sum(i)) &lt; min) min = sm;
  20.     for (int i = m; i &lt;= n; i++)
  21.         if (sum(i) == min) cnt++;
  23.     return cnt;
  24. }

Or less brute force:

  1. size_t minsum(int m, int n){
  2.     int min = sum(m);
  3.     int sm;
  4.     size_t cnt = 1;
  6.     for (int i = m + 1; i &lt;= n; i++)
  7.     {
  8.         sm = sum(i);
  9.         if (sm &lt; min) 
  10.         {
  11.             min = sm; 
  12.             cnt = 1;
  13.         }
  14.         else if(sm == min) cnt++;
  15.     }
  17.     return cnt;
  18. }

答案3

得分: 0

代码中存在的问题：

  1. 函数中的 cnt 和 min 没有被初始化（也没有定义）。

  2. 当找到新的最小值时，cnt 没有被重置。

你的代码可以很容易修复，如下所示：

  1. int minSum(int m, int n){
  2.     int cnt = 0;        // 初始化 cnt
  3.     int min = INT_MAX;  // 将 min 初始化为一个较大的值
  5.     for (int i = m; i <= n; i++){
  6.         int sm = sum(i);
  7.         if (sm < min) {
  8.             cnt = 0;   // 重置 cnt
  9.             min = sm;
  10.         }
  11.         if (min == sm)  cnt++;
  12.     }
  13.     return cnt;
  14. }
英文:

Problems:

  1. cnt and min not initialized in the function (nor defined)

  2. cnt is not reset when a new minimum value is found.

Your code is easy to fix. Like:

  1. int minSum(int m, int n){
  2.     int cnt = 0;        // Initialize cnt
  3.     int min = INT_MAX;  // Initialize min to a high value
  5.     for (int i=m; i&lt;=n; i++){
  6.         int sm=sum(i);
  7.         if (sm&lt;min)
  8.         {
  9.             cnt = 0;   // Reset cnt
  10.             min=sm;
  11.         }
  12.         if (min==sm)  cnt++;
  13.     }
  14.     return cnt;
  15. }

huangapple
  • 本文由 发表于 2023年2月6日 21:15:25
  • 转载请务必保留本文链接：https://go.coder-hub.com/75361795.html
  • c
  • digits
  • function-definition
  • min
  • sum
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