Codeforces Round #530 (Div. 2) C. Postcard(构造)

#include <bits/stdc++.h>
using namespace std;
string str;
int n;

int main()
{
	cin>>str;
	scanf("%d",&n);
	int len = str.length();
	int xx = 0, yy = 0;
	int pos;
	for(int i=0;i<len;i++){
		if(str[i] == '?') xx ++;
		if(str[i] == '*'){
			pos = i;
			yy ++;
		}
	}
	int ans = len - xx - yy;
	if(ans == n){
		for(int i=0;i<len;i++){
			if(str[i] != '?' && str[i] != '*')
				cout<<str[i];
		}
		puts("");
	}
	else if(ans < n){
		if(yy != 0){
			string s;
			for(int i=0;i<len;i++){
				if(i == pos - 1){
					for(int j=0;j<n - ans;j++){
						s += str[i];
					}
				}
				if(str[i] != '?' && str[i] != '*') s += str[i];
			}
			cout<<s<<endl;
		}
		else puts("Impossible");
	}
	else{
		if(ans - xx - yy > n) puts("Impossible");
		else{
			string s;
			int cnt = 0;
			for(int i=0;i<len-1;i++){
				if(cnt < ans - n && (str[i+1] == '?' || str[i+1] == '*')){
					cnt ++;
					continue;
				}
				if(str[i] != '?' && str[i] != '*'){
					s += str[i];
				}
			}
			if(str[len-1] != '?' && str[len-1] != '*')s += str[len-1];
			cout<<s<<endl;
		}
	}
	return 0;
}