Gym 101047M Removing coins in Kem Kadrãn

给定一个序列，只能拿走D，隔壁的会翻转，问能否全部拿走。

注意到如果能拿走的话，拿D的顺序是没关系的。模拟即可

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <algorithm>
using namespace std;
#define inf (0x3f3f3f3f)
typedef long long int LL;

#include <iostream>
#include <sstream>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <string>
const int maxn = 1e5+20;
char str[maxn];
char sub[maxn];

void work ()
{
    char book[256];
    book['B']='D';
    book['D']='B';
    int n;
    scanf("%d",&n);
    scanf("%s",str+1);
    strcpy(sub+1,str+1);

    int did=0;
    int cnt=0;
    vector<int>ans;
    int begin=1;
    int flag=0;
    for (int i=1;i<=n;++i)
    {
        if (str[i]=='D')
        {
            flag=1;
            cnt++;
            did += cnt;
            cnt=0;
            str[i+1]=book[str[i+1]];
            for (int j=i;j>=begin;--j)
            {
                ans.push_back(j);
            }
            begin=i+1;
        }
        else cnt++;
    }

    if (did==n)
    {
        printf ("Y
");
        for (int i=0;i<ans.size();++i)
        {
            printf ("%d ",ans[i]);
        }
        printf ("
");
    }
    else printf ("N
");
    return ;
}


int main()
{
#ifdef local
    freopen("data.txt","r",stdin);
#endif
    int t;
    scanf ("%d",&t);
    while(t--) work();
    return 0;
}