Little Pony and Permutation
Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 639 Accepted Submission(s): 342
Problem Description
As a unicorn, the ability of using magic is the distinguishing feature among other kind of pony. Being familiar with composition and decomposition is the fundamental course for a young unicorn. Twilight Sparkle is interested in the decomposition of permutations. A permutation of a set S = {1, 2, ..., n} is a bijection from S to itself. In the great magician —— Cauchy's two-line notation, one lists the elements of set S in the first row, and then for each element, writes its image under the permutation below it in the second row. For instance, a permutation of set {1, 2, 3, 4, 5} σ can be written as:
Here σ(1) = 2, σ(2) = 5, σ(3) = 4, σ(4) = 3, and σ(5) = 1.
Twilight Sparkle is going to decompose the permutation into some disjoint cycles. For instance, the above permutation can be rewritten as:
Help Twilight Sparkle find the lexicographic smallest solution. (Only considering numbers).
Input
Input
contains multiple test cases (less than 10). For each test case, the
first line contains one number n (1<=n<=10^5). The second line
contains n numbers which the i-th of them(start from 1) is σ(i).
Output
For each case, output the corresponding result.
Sample Input
5
2 5 4 3 1
3
1 2 3
Sample Output
(1 2 5)(3 4)
(1)(2)(3)
= = 把a数组设为bool 型,无限WA。。。我真是。。。本来1A的
题意:就是找循环。比如说 1 ->2 -> 5->1 所以 (1,2,5)是一个循环。
#include <stdio.h> #include <math.h> #include <iostream> #include <algorithm> #include <string.h> #include <vector> using namespace std; const int N = 100005; bool vis[N]; int res[N],a[N]; int main() { int n; while(scanf("%d",&n)!=EOF){ for(int i=1;i<=n;i++){ scanf("%d",&a[i]); } memset(vis,false,sizeof(vis)); for(int i=1;i<=n;i++){ int j=i; if(vis[j]) continue; int id = 0; while(!vis[j]){ res[id++] = j; vis[j]=true; j = a[j]; } printf("("); for(int i=0;i<id-1;i++){ printf("%d ",res[i]); } printf("%d)",res[id-1]); } printf(" "); } return 0; }