Given any permutation of the numbers {0, 1, 2,..., N−1}, it is easy to sort them in increasing order. But what if Swap(0, *)
is the ONLY operation that is allowed to use? For example, to sort {4, 0, 2, 1, 3} we may apply the swap operations in the following way:
Swap(0, 1) => {4, 1, 2, 0, 3}
Swap(0, 3) => {4, 1, 2, 3, 0}
Swap(0, 4) => {0, 1, 2, 3, 4}
Now you are asked to find the minimum number of swaps need to sort the given permutation of the first Nnonnegative integers.
Input Specification:
Each input file contains one test case, which gives a positive N (≤) followed by a permutation sequence of {0, 1, ..., N−1}. All the numbers in a line are separated by a space.
Output Specification:
For each case, simply print in a line the minimum number of swaps need to sort the given permutation.
Sample Input:
10
3 5 7 2 6 4 9 0 8 1
Sample Output:
9
1 #include <iostream> 2 using namespace std; 5 int m = 0, N, nums[100005], flag = 1, index = 1; 6 int main() 7 { 8 cin >> N; 9 for (int i = 0; i < N; ++i) 10 cin >> nums[i]; 11 12 while (index<N) 13 { 14 while (nums[0] != 0) 15 { 16 swap(nums[0], nums[nums[0]]); 17 ++m; 18 } 19 for (; index < N; ++index)//使用index,不用每次从0开始遍历 20 { 21 if (index != nums[index]) 22 { 23 swap(nums[0], nums[index]); 24 ++m; 25 break; 26 } 27 } 28 } 29 cout << m << endl; 30 return 0; 31 }
原文地址:https://www.cnblogs.com/zzw1024/p/11306371.html
时间: 2024-10-29 04:25:19