1 /***************************************************************** 2 created:    2014/09/13 16:16 3 filename:    remove-duplicates-from-sorted-array.cpp 4 author:        Justme0 (http://blog.csdn.net/justme0) 5  6 purpose:    有序数组中，有至少三个相同元素时删掉只留两个 7 https://oj.leetcode.com/problems/remove-duplicates-from-sorted-array-ii/ 8 *****************************************************************/ 9 10 #include <iostream>11 #include <cassert>12 #include <vector>13 using namespace std;14 15 class Solution {16 public:17     int removeDuplicates(int A[], int n) {18         if (n <= 2) {19             return n;20         }21 22         vector<int> iVec;23         iVec.push_back(A[0]);24         for (int i = 1; i < n - 1; ++i) {25             if (!(A[i - 1] == A[i] && A[i] == A[i + 1])) {26                 iVec.push_back(A[i]);27             }28         }29         iVec.push_back(A[n - 1]);30 31         assert(iVec.size() <= unsigned(n));32         for (unsigned i = 0; i < iVec.size(); ++i) {33             A[i] = iVec[i];34         }35 36         return iVec.size();37     }38 };39 40 class Solution2 {41 public:42     int removeDuplicates(int A[], int n) {43         if (n <= 2) {44             return n;45         }46 47         int len = 2;48         for (int i = 2; i < n; ++i) {49             if (A[i] != A[len - 2]) {50                 A[len] = A[i];51                 ++len;52             }53         }54         assert(len <= n);55 56         return len;57     }58 };59 60 int main(int argc, char **argv) {61     int arr[] = {1, 1, 2, 2, 3};62     int len = sizeof arr / sizeof *arr;63     int new_len = Solution2().removeDuplicates(arr, len);64     for (int i = 0; i < new_len; ++i) {65         cout << arr[i] << endl;66     }67 68     system("PAUSE");69     return 0;70 }