func_code_string: #include <bits/stdc++.h>   using namespace std;   const double eps = 1e-8;   const double pi = acos(-1);   const long long inf = 0x3f3f3f3f3f3f3f3f;   const int INF = 0x3f3f3f3f;   const int MAX = 2e5 + 10;   const long long mod = 1e9 + 7;   long long gcd(long long a, long long b) { return b ? gcd(b, a % b) : a; }   char c[3] = { R ,  G ,  B };   int main() {     int t;     cin >> t;     while (t--) {       int dif[3] = {0};       int n, k;       cin >> n >> k;       string s;       cin >> s;       for (int i = (0); i < (3); ++i) {         for (int j = (0); j < (k); ++j) {           if (s[j] != c[(j + i) % 3]) dif[i]++;         }       }       int ans = 0;       ans = min(dif[0], min(dif[1], dif[2]));       for (int i = 1; i + k - 1 < n; i++) {         int a0 = dif[0], a1 = dif[1], a2 = dif[2];         dif[0] = a2 - (s[i - 1] ==  B  ? 0 : 1) +                  (s[i + k - 1] == c[(k - 1) % 3] ? 0 : 1);         dif[1] =             a0 - (s[i - 1] ==  R  ? 0 : 1) + ((s[i + k - 1] == c[k % 3]) ? 0 : 1);         dif[2] = a1 - (s[i - 1] ==  G  ? 0 : 1) +                  ((s[i + k - 1] == c[(k + 1) % 3]) ? 0 : 1);         ans = min(ans, min(dif[0], min(dif[1], dif[2])));       }       cout << ans <<   n ;     }   }   