题解 | #位数求和#

#include<iostream>
#include<string>
#include<vector>
using namespace std;

long long sum(int n, int m) {
    // write code here
    long long res = 0;
    int minVal = 1;
    int maxVal = 9;
    for (int i = 1; i < n; i++) {
        minVal *= 10;
        maxVal *= 10;
        maxVal += 9;
    }
    cout << minVal << "  " << maxVal << endl;
    for (int i = minVal; i <= maxVal; i++) {
        int tempVal = i;
        int tempSum = 0;
        while (tempVal > 0) {
            tempSum += tempVal % 10;
            tempVal /= 10;
        }
        if (tempSum == m) {
            res += i;
        }
    }
    cout << res << endl;
    return res;
}

int main() {
    sum(2, 3);
}