D. Diverse Garland：题目

什么脑瘫题目！！！可恶，和dp有什么关系？但是强迫症让我不得不写，空一个很难受！！

#include <bits/stdc++.h>
using namespace std;
#define int long long
vector<int> a((int)6e5);
vector<int> b((int)6e5), c((int)6e5);
const int mod = 1e9 + 7;
map<int, int> mp1, mp2;
string str;
signed main()
{int n;cin>>n;cin>>str;str = "1"+str+"1";int cou = 0;for (int i=2;i<=n;i++){if (str[i]==str[i-1]) {cou++;if (str[i-1]=='B'){if (str[i+1]=='G') str[i] = 'R';else str[i] = 'G';}else if (str[i-1]=='G'){if (str[i+1]=='R') str[i] = 'B';else str[i] = 'R';}else {if (str[i+1]=='B') str[i] = 'G';else str[i] = 'B';}}}cout<<cou<<endl;for (int i=1;i<=n;i++) cout<<str[i];
}