https://codeforces.ml/contest/1465/problem/E
好题好题 做不来的都是好题[滑稽]
写的太好了555 羡慕这样的博客
https://www.cnblogs.com/dysyn1314/p/14183815.html
图片截取自上述链接
1 #include<bits/stdc++.h>
2 #define ll long long
3 using namespace std;
4 ll n, T;
5 string s;
6 ll cnt[30];
7 int main(){
8 cin >> n >> T;
9 cin >> s;
10
11 ll tmp = 0;
12 tmp += (1ll << (s[n - 1] - 'a'));
13 tmp -= (1ll << (s[n - 2] - 'a'));
14
15 for(int i = 0 ; i < n - 2 ; i++){
16 tmp -= (1ll << (s[i] - 'a'));
17 }
18 for(int i = 0 ; i < n - 2 ; i++){
19 cnt[s[i] - 'a']++;
20 }//最后两位不计入cnt
21
22 if(T < tmp){
23 cout << "NO" << endl;
24 return 0;
25 }else{
26 T -= tmp;
27 }
28
29 for(int i = 25 ; i >= 0 ; i--){
30 ll p = (1ll << (i + 1));//多移一位，减法到加法 两倍
31 ll k = min(cnt[i], T / p);
32 T -= k * p;
33 }
34
35 if(!T){
36 cout << "YES" << endl;
37 }else{
38 cout << "NO" << endl;
39 }
40
41 return 0;
42 }