1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
# include <bits/stdc++.h>
typedef long long ll;
using namespace std;
# define For(i , l , r) for(int i = (l); i <= (r); i++)
# define Rep(i , n) For(i , 0 , (n) - 1)
# define size(x) (ll)x.size()
# define all(x) x.begin(),x.end()
# define MAXN 8002
const ll inf = 1e9 + 7;
const ll mod = 998244353;
ll n , m , k , ans = 0 , qq , t , timer = 0 , s;
int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    cin >> n >> k >> t;
    string s;
    cin >> s;
    s = '*' + s;
    ll have = 0 , have2 = 0;
    vector<ll>pref(n + 5) , suf(n + 5) , pref2(n + 5);
    For (i , 1 , size(s) - 1) {
        pref2[i] = pref2[i - 1] + (s[i] == '1');
        if (s[i] == '1' || s[i] == '2') have++;
        if (s[i] == '2') have2++;
    }
    For (i , 1 , size(s) - 1) {
          pref[i] = pref[i - 1] + (s[i] == '2');
    }
    for (int i = size(s) - 1; i; i--) {
          suf[i] = suf[i + 1] + (s[i] == '2');
    }
    ans = -1;
    For (i , 1 , size(s) - 1) {
        For (j , i , size(s) - 1) {
             if (i - t - 1 >= 0 && j + t + 1 <= size(s)) {
                   ll sum = pref2[j] - pref2[i - 1] + 
                   pref[j] - pref[i - 1];
                   ll need = max((have - k) - sum , 0LL);
                   ll can = pref[i - t - 1] + suf[j + t + 1];
                   if (need > can) continue;
                   ll res = i - t - 1 + (n - (j + t)) - need;
                   if (ans < res) {
                        ans = max(ans , res);
                   }
             }
        }
    }
    if (have - k <= have2) {
         ll need = max(0LL , have - k);
         cout << n - need;
    }
    else {
        if (ans < 0) cout << -1;
        else cout << ans;
    }
}
/*

*/