/* ID: lucien23 PROG: sort3 LANG: C++ */ #include <iostream> #include <fstream> #include <vector> #include <algorithm> using namespace std; void exchange(int nums[], int begin, int end, int N, int x); int sum = 0; int main() { ifstream infile("sort3.in"); ofstream outfile("sort3.out"); if(!infile || !outfile) { cout << "file operation failure!" << endl; return -1; } int N; infile >> N; int *nums = new int[N]; int count1, count2, count3; count1 = count2 = count3 = 0; for (int i=0; i<N; i++) { infile >> nums[i]; switch (nums[i]) { case 1: count1++; break; case 2: count2++; break; case 3: count3++; break; default: break; } } exchange(nums, 0, count1, N, 1); exchange(nums, count1, count1+count2, N, 2); outfile << sum << endl; return 0; } /* *交换时将大的交换到后面,小的交换到前面 */ void exchange(int nums[], int begin, int end, int N, int x) { int count0 = 0; vector<int> vecNum; for (int i=begin; i<end; i++) { if (nums[i] != x) { count0++; vecNum.push_back(nums[i]); nums[i] = x; } } sum += count0; sort(vecNum.begin(), vecNum.end()); for (int i=end, j=0; i<N && count0>0; i++) { if (nums[i] == 1) { nums[i] = vecNum[j]; j++; count0--; } } }
USACO Section 2.1 Sorting a Three-Valued Sequence,布布扣,bubuko.com
时间: 2024-10-13 11:59:51