POTD_16_OCT_2024_TwoSwaps.cpp

class Solution { 
public: 
void doOneSwap(int &n, vector<int> &arr) { 
  for (int i = 0; i < n; i++) { 
    if (arr[i] != i + 1) { 
      for (int j = i + 1; j < n; j++) { 
        if (arr[j] == i + 1) { 
          swap(arr[i], arr[j]); 
          return; 
        } 
      } 
    } 
  } 
} 
bool checkSorted(vector<int> &arr) { 
  int n = arr.size(); 
  int misMatch = 0; 
  for (int i = 0; i < n; i++) { 
    if (arr[i] != i + 1) misMatch++; } 
  if (n == 1) return false; 
  if (misMatch == 0 || misMatch == 3) return true; if (misMatch != 4) return false; 
  doOneSwap(n, arr); 
  doOneSwap(n, arr); 
  for (int i = 0; i < n; i++) { 
    if (arr[i] != i + 1) 
      return false; } 
  return true; } };