位数总和为十的第 n 个数字
给定一个整数值 n，求和为 10 的第 n 个正整数。 例:
Input: n = 2
Output: 28
The first number with sum of digits as
10 is 19\. Second number is 28.
Input: 15
Output: 154
方法 1(简单): 我们遍历所有的数字。对于每个数字，我们找到数字的总和。当我们找到第 n 个数字的总和为 10 时，我们停止。
C++
// Simple CPP program to find n-th number
// with sum of digits as 10.
#include <bits/stdc++.h>
using namespace std;
int findNth(int n)
{
int count = 0;
for (int curr = 1;; curr++) {
// Find sum of digits in current no.
int sum = 0;
for (int x = curr; x > 0; x = x / 10)
sum = sum + x % 10;
// If sum is 10, we increment count
if (sum == 10)
count++;
// If count becomes n, we return current
// number.
if (count == n)
return curr;
}
return -1;
}
int main()
{
printf("%d\n", findNth(5));
return 0;
}
Java 语言(一种计算机语言，尤用于创建网站)
// Java program to find n-th number
// with sum of digits as 10.
import java.util.*;
import java.lang.*;
public class GFG {
public static int findNth(int n)
{
int count = 0;
for (int curr = 1;; curr++) {
// Find sum of digits in current no.
int sum = 0;
for (int x = curr; x > 0; x = x / 10)
sum = sum + x % 10;
// If sum is 10, we increment count
if (sum == 10)
count++;
// If count becomes n, we return current
// number.
if (count == n)
return curr;
}
}
public static void main(String[] args)
{
System.out.print(findNth(5));
}
}
// Contributed by _omg
Python 3
# Python3 program to find n-th number
# with sum of digits as 10.
import itertools
# function to find required number
def findNth(n):
count = 0
for curr in itertools.count():
# Find sum of digits in current no.
sum = 0
x = curr
while(x):
sum = sum + x % 10
x = x // 10
# If sum is 10, we increment count
if (sum == 10):
count = count + 1
# If count becomes n, we return current
# number.
if (count == n):
return curr
return -1
# Driver program
if __name__=='__main__':
print(findNth(5))
# This code is contributed by
# Sanjit_Prasad
C
// C# program to find n-th number
// with sum of digits as 10.
using System;
class GFG {
public static int findNth(int n)
{
int count = 0;
for (int curr = 1;; curr++) {
// Find sum of digits in current no.
int sum = 0;
for (int x = curr; x > 0; x = x / 10)
sum = sum + x % 10;
// If sum is 10, we increment count
if (sum == 10)
count++;
// If count becomes n, we
// return current number.
if (count == n)
return curr;
}
}
// Driver Code
static public void Main()
{
Console.WriteLine(findNth(5));
}
}
// This code is contributed
// by Sach_Code
服务器端编程语言（Professional Hypertext Preprocessor 的缩写）
<?php
// Simple PHP program to find n-th
// number with sum of digits as 10.
function findNth($n)
{
$count = 0;
for ($curr = 1; ; $curr++)
{
// Find sum of digits in
// current no.
$sum = 0;
for ($x = $curr;
$x > 0; $x = $x / 10)
$sum = $sum + $x % 10;
// If sum is 10, we increment
// count
if ($sum == 10)
$count++;
// If count becomes n, we return
// current number.
if ($count == $n)
return $curr;
}
return -1;
}
// Driver Code
echo findNth(5);
// This code is contributed by Sach .
?>
java 描述语言
<script>
// Simple JavaScript program to find n-th number
// with sum of digits as 10.
function findNth(n)
{
let count = 0;
for (let curr = 1;; curr++) {
// Find sum of digits in current no.
let sum = 0;
for (let x = curr; x > 0; x = Math.floor(x / 10))
sum = sum + x % 10;
// If sum is 10, we increment count
if (sum == 10)
count++;
// If count becomes n, we return current
// number.
if (count == n)
return curr;
}
return -1;
}
document.write(findNth(5));
// This code is contributed by Surbhi Tyagi.
</script>
Output
55
方法 2(有效率): 如果我们仔细观察，可以注意到所有 9 的倍数都出现在等差数列 19、28、37、46、55、64、73、82、91、100、109、…… 但是，上述数列中有一些数字的位数之和不是 10，例如 100。所以我们不是一个接一个地检查，而是从 19 开始，递增 9。
C++
// Simple CPP program to find n-th number
// with sum of digits as 10.
#include <bits/stdc++.h>
using namespace std;
int findNth(int n)
{
int count = 0;
for (int curr = 19;; curr += 9) {
// Find sum of digits in current no.
int sum = 0;
for (int x = curr; x > 0; x = x / 10)
sum = sum + x % 10;
// If sum is 10, we increment count
if (sum == 10)
count++;
// If count becomes n, we return current
// number.
if (count == n)
return curr;
}
return -1;
}
int main()
{
printf("%d\n", findNth(5));
return 0;
}
Java 语言(一种计算机语言，尤用于创建网站)
// Java program to find n-th number
// with sum of digits as 10.
import java.util.*;
import java.lang.*;
public class GFG {
public static int findNth(int n)
{
int count = 0;
for (int curr = 19;; curr += 9) {
// Find sum of digits in current no.
int sum = 0;
for (int x = curr; x > 0; x = x / 10)
sum = sum + x % 10;
// If sum is 10, we increment count
if (sum == 10)
count++;
// If count becomes n, we return current
// number.
if (count == n)
return curr;
}
}
public static void main(String[] args)
{
System.out.print(findNth(5));
}
}
// Contributed by _omg
Python 3
# Python3 program to find n-th
# number with sum of digits as 10.
def findNth(n):
count = 0;
curr = 19;
while (True):
# Find sum of digits in
# current no.
sum = 0;
x = curr;
while (x > 0):
sum = sum + x % 10;
x = int(x / 10);
# If sum is 10, we increment
# count
if (sum == 10):
count+= 1;
# If count becomes n, we return
# current number.
if (count == n):
return curr;
curr += 9;
return -1;
# Driver Code
print(findNth(5));
# This code is contributed
# by mits
C
// C# program to find n-th number
// with sum of digits as 10.
using System;
class GFG {
public static int findNth(int n)
{
int count = 0;
for (int curr = 19;; curr += 9) {
// Find sum of digits in
// current no.
int sum = 0;
for (int x = curr;
x > 0; x = x / 10)
sum = sum + x % 10;
// If sum is 10, we increment
// count
if (sum == 10)
count++;
// If count becomes n, we return
// current number.
if (count == n)
return curr;
}
}
// Driver Code
static public void Main()
{
Console.WriteLine(findNth(5));
}
}
// This code is contributed
// by Sach_Code
服务器端编程语言（Professional Hypertext Preprocessor 的缩写）
<?php
// Simple PHP program to find n-th
// number with sum of digits as 10.
function findNth($n)
{
$count = 0;
for ($curr = 19; ;$curr += 9)
{
// Find sum of digits in
// current no.
$sum = 0;
for ($x = $curr; $x > 0;
$x = (int)$x / 10)
$sum = $sum + $x % 10;
// If sum is 10, we increment
// count
if ($sum == 10)
$count++;
// If count becomes n, we return
// current number.
if ($count == $n)
return $curr;
}
return -1;
}
// Driver Code
echo findNth(5);
// This code is contributed
// by Sach_Code
?>
java 描述语言
<script>
// Simple Javascript program to find n-th
// number with sum of digits as 10.
function findNth(n)
{
let count = 0;
for (let curr = 19; ;curr += 9)
{
// Find sum of digits in
// current no.
let sum = 0;
for (let x = curr; x > 0;
x = parseInt(x / 10))
sum = sum + x % 10;
// If sum is 10, we increment
// count
if (sum == 10)
count++;
// If count becomes n, we return
// current number.
if (count == n)
return curr;
}
return -1;
}
// Driver Code
document.write(findNth(5));
// This code is contributed
// by gfgking
</script>
Output
55
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