Color Stripe
Time Limit:2000MS Memory Limit:262144KB 64bit IO Format:%I64d & %I64u
Submit Status Practice CodeForces 219C
Description
A colored stripe is represented by a horizontal row of n square cells, each cell is pained one of k colors. Your task is to repaint the minimum number of cells so that no two neighbouring cells are of the same color. You can use any color from 1 to k to repaint the cells.
Input
The first input line contains two integers n and k (1 ≤ n ≤ 5·105; 2 ≤ k ≤ 26). The second line contains n uppercase English letters. Letter "A" stands for the first color, letter "B" stands for the second color and so on. The first k English letters may be used. Each letter represents the color of the corresponding cell of the stripe.
Output
Print a single integer — the required minimum number of repaintings. In the second line print any possible variant of the repainted stripe.
Sample Input
Input
6 3ABBACC
Output
2ABCACA
Input
3 2BBB
Output
1BAB
1 #include <iostream>
2 #include <cstdio>
3 #include <cstring>
4 using namespace std;
5 int main()
6 {
7 int n,m;
8 char s[500100];
9 while(scanf("%d%d",&n,&m)!=EOF)
10 {
11 scanf("%s",s);
12 int i,ans=0;
13 m+=64;
14 if(n==1)
15 {
16 cout<<ans<<endl<<s<<endl;
17 continue;
18 }
19 if(m==66)
20 {
21 int l=0,r=0;
22 for(i=0;i<n;i++)
23 if(i%2==0)
24 {
25 if(s[i]==‘B‘) l++;
26 else r++;
27 }
28 else
29 {
30 if(s[i]==‘A‘) l++;
31 else r++;
32 }
33 if(l<r)
34 {
35 cout<<l<<endl;
36 for(i=0;i<n;i++)
37 if(i%2==0) cout<<‘A‘;
38 else cout<<‘B‘;
39 }
40 else
41 {
42 cout<<r<<endl;
43 for(i=0;i<n;i++)
44 if(i%2==0) cout<<‘B‘;
45 else cout<<‘A‘;
46 }
47 cout<<endl;
48 continue;
49 }
50 s[n]=‘#‘;
51 for(i=1;i<n;i++)
52 if(s[i]==s[i-1])
53 {
54 ans++;
55 for(int j=65;j<=m;j++)
56 if(j==s[i]||j==s[i+1]) continue;
57 else
58 {
59 s[i]=j;
60 break;
61 }
62 }
63 s[n]=‘\0‘;
64 cout<<ans<<endl<<s<<endl;
65
66 }
67 return 0;
68 }