1513C. Add One

1513C. Add One

具体代码如下

#include<bits/stdc++.h>

using namespace std;

const int N = 200010, mod = 1e9 + 7;

int n, m;
int dp[N][10], sum[N];

void init()
{
	dp[0][0] = 1, dp[0][1] = 1, sum[0] = 2;
	for(int i = 1; i < N; ++ i)
		for(int j = 0; j <= 9; ++ j)
		{
			if(j) dp[i][j] = dp[i - 1][j - 1];
			if(!j || j == 1) dp[i][j] = (dp[i][j] + dp[i - 1][9]) % mod;
			sum[i] = (sum[i] + dp[i][j]) % mod;
		}
}

int main()
{
	
	int T;
	scanf("%d", &T);
	
	init();
	
	while(T --)
	{
		scanf("%d%d", &n, &m);
		
		vector<int> v;
		while(n)
		{
			v.push_back(n % 10);
			n /= 10;
		}
		
		int ans = 0;
		for(auto i : v)
		{
			int x = 10 - i;
			if(x > m) ans = (ans + 1) % mod;
			else ans = (ans + sum[m - x]) % mod;
		}
		cout << ans << endl;
	}
	
	return 0;
}