func_code_string: #include <bits/stdc++.h>   using namespace std;   const int N = 22e4;   char s[N * 2];   int l[N * 2], r[N * 2];   int main() {     ios::sync_with_stdio(0);     int n, k;     cin >> n >> k >> s;     for (int i = 0; i < n; i++) s[i + n] = s[i];     for (int i = 0, lx = -2e9; i < n * 2; i++) {       if (s[i] == s[i + 1]) lx = i + 1;       l[i + 1] = lx;     }     for (int i = n * 2 - 1, rx = 2e9; i > 0; i--) {       if (s[i] == s[i - 1]) rx = i - 1;       r[i - 1] = rx;     }     for (int i = 0; i < n; i++) {       if (i + n - l[i + n] < r[i] - i) {         if (i + n - l[i + n] <= k)           cout << s[l[i + n]];         else if (k & 1)           cout << (s[i] ==  W  ?  B  :  W );         else           cout << s[i];       } else {         if (r[i] - i <= k)           cout << s[r[i]];         else if (k & 1)           cout << (s[i] ==  W  ?  B  :  W );         else           cout << s[i];       }     }     return 0;   }   