17-09-03模拟赛

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<algorithm>
 4 using namespace std;
 5 inline int in(){
 6     int x=0;bool f=0; char c;
 7     for (;(c=getchar())<‘0‘||c>‘9‘;f=c==‘-‘);
 8     for (x=c-‘0‘;(c=getchar())>=‘0‘&&c<=‘9‘;x=(x<<3)+(x<<1)+c-‘0‘);
 9     return f?-x:x;
10 }
11 const char ch[3]={‘B‘,‘G‘,‘R‘};
12 int sum[3],a[4],b[4],c[4],cnt[3],n;
13 char s[205];
14 int main()
15 {
16     n=in();if (!n) return 0;scanf("%s",&s);
17     for (int i=0;i<n;++i) {
18         switch (s[i]){
19             case ‘B‘:++sum[0];break;
20             case ‘G‘:++sum[1];break;
21             case ‘R‘:++sum[2];break;
22         }
23     }
24     for (int i=0;i<3;++i){
25         if (!sum[i]) a[++cnt[0]]=i;
26         else if (sum[i]==1) b[++cnt[1]]=i;
27         else c[++cnt[2]]=i;
28     }
29     if (!cnt[0]) {printf("BGR");return 0;}
30     if (cnt[0]==2) {printf("%c",cnt[1]?ch[b[1]]:ch[c[1]]);return 0;}
31     if (!cnt[1]) {printf("BGR");return 0;}
32     if (cnt[1]==2) {printf("%c",ch[a[1]]);return 0;}
33     if (cnt[1]==1) {ch[a[1]]<ch[b[1]]?printf("%c%c",ch[a[1]],ch[b[1]]):printf("%c%c",ch[b[1]],ch[a[1]]);return 0;}
34     return 0;
35 }