USACO 1.1.4 Broken Necklace
2013-05-03 21:53
351 查看
Broken Necklace
You have a necklace of N red, white, or blue beads (3<=N<=350) some of which are red, others blue, and others white, arranged at random. Here are two examples for n=29:1 2 1 2 r b b r b r r b r b b b r r b r r r w r b r w w b b r r b b b b b b r b r r b r b r r r b r r r r r r b r b r r r w Figure A Figure B r red bead b blue bead w white bead
The beads considered first and second in the text that follows have been marked in the picture.
The configuration in Figure A may be represented as a string of b's and r's, where b represents a blue bead and r represents a red one, as follows: brbrrrbbbrrrrrbrrbbrbbbbrrrrb .
Suppose you are to break the necklace at some point, lay it out straight, and then collect beads of the same color from one end until you reach a bead of a different color, and do the same for the other end (which
might not be of the same color as the beads collected before this).
Determine the point where the necklace should be broken so that the most number of beads can be collected.
Example
For example, for the necklace in Figure A, 8 beads can be collected, with the breaking point either between bead 9 and bead 10 or else between bead 24 and bead 25.In some necklaces, white beads had been included as shown in Figure B above. When collecting beads, a white bead that is encountered may be treated as either red or blue and then painted with the desired
color. The string that represents this configuration will include the three symbols r, b and w.
Write a program to determine the largest number of beads that can be collected from a supplied necklace.
PROGRAM NAME: beads
INPUT FORMAT
Line 1: | N, the number of beads |
Line 2: | a string of N characters, each of which is r, b, or w |
SAMPLE INPUT (file beads.in)
29 wwwbbrwrbrbrrbrbrwrwwrbwrwrrb
OUTPUT FORMAT
A single line containing the maximum of number of beads that can be collected from the supplied necklace.SAMPLE OUTPUT (file beads.out)
11
OUTPUT EXPLANATION
Consider two copies of the beads (kind of like being able to runaround the ends). The string of 11 is marked.original 'split' v wwwbbrwrbrbrrbrbrwrwwrbwrwrrb|wwwbbrwrbrbrrbrbrwrwwrbwrwrrb ******|***** rrrrrb|bbbbb <-- assignments 5 x r 6 x b <-- 11 total
这题真心给跪了,各种调不过 , 一开始考虑环形,好复杂,后来德恩哥提示我可以把这个字符串重复一遍,这样就不用找环了,恍然大悟,迅速AC!
/* ID: xinming2 PROG: beads LANG: C++ */ #include <cstdio> #include <cmath> #include <algorithm> #include <iostream> #include <cstring> #include <map> #include <string> using namespace std; char s[750]; int main() { freopen("beads.in","r",stdin); freopen("beads.out","w" , stdout); int n , i , j , k; while(scanf("%d",&n)!=EOF) { scanf("%s",&s); for(i = n ; i < 2 * n; i++) { s[i] = s[i - n]; } int maxn = 0; int num; char a = 'x' , b = 'x'; for( i = 0 ; i < 2 * n ; i++) { int va = 0 , vb = 0; if(s[i] != s[i + 1]) { num = 2; if(!va&&s[i] != 'w') { a = s[i]; va = 1; } if(!vb&&s[i + 1] != 'w') { b = s[i + 1]; vb = 1; } for(j = i - 1 ; j >=0 ; j--) { if(!va&&s[j] != 'w') { a = s[j]; va = 1; } if(s[j] == a||s[j] == 'w')num++; else break; } for(k = i + 2 ; k < 2 * n ; k++) { if(!vb&&s[k] != 'w') { b = s[k]; vb = 1; } if(s[k] == b||s[k] == 'w')num++; else break; } maxn = max(maxn , num); } } maxn = min(maxn , n); if(maxn == 0)maxn = n; printf("%d\n",maxn); } return 0; } /* 77 rwrwrwrwrwrwrwrwrwrwrwrwbwrwbwrwrwrwrwrwrwrwrwrwrwrwrwrwrwrwrwrwrwrwrwrwrwrwr */
相关文章推荐
- USACO1.1.4 Broken Necklace (beads)
- 【USACO题库】1.1.4 Broken Necklace破碎的项链
- 【USACO题库】1.1.4 Broken Necklace破碎的项链
- usaco 1.1.4 Broken Necklace 一道题可以犯多少脑残
- USACO 1.1.4 Broken Necklace
- USACO 1.1.4 Broken Necklace(模拟)
- USACO 1.1.4 Broken Necklace
- usaco1.1.4 Broken Necklace 题解
- usaco1.1.4 Broken Necklace破碎的项链
- USACO1.1.4 - Broken Necklace
- USACO 1.1.4 Broken Necklace(beads)
- USACO-1.1.4 Broken necklace
- USACO1.1.4 Broken Necklace
- [USACO1.1.4]坏掉的项链Broken Necklace
- USACO 1.1.4 - Broken Necklace(DP)
- 【USACO题库】1.1.4 Broken Necklace破碎的项链
- USACO 1.1.4 Broken Necklace
- USACO之Section1.1.4 Broken Necklace
- USACO1.1.4 Broken Necklace 破碎的项链
- Usaco 1.1.4 破碎的项链(Broken Necklace)