rotateMatrix.cpp

#include <climits>
#include <iostream>
#include <unordered_map>
#include <vector>
using namespace std;

int n = 4;
unordered_map<int, int> map;
int newPos[2];
int startPos[2];
int temp = INT_MIN;

bool switched(unordered_map<int, int>::iterator start,
              unordered_map<int, int>::iterator end, int row, int col) {
  for (auto i = start; i != end; i++) {
    if (i->first == row && i->second == col) return true;
  }
  return false;
}

int* correctPos(int pos[]) {
  newPos[0] = pos[1];
  newPos[1] = n + 1 - pos[0];
  return &newPos[0];
}

void changePos(vector<vector<int>>& matrix, int* pos, int* newPos) {
  while (startPos != newPos) {
    cout << pos[0] << " " << pos[1] << "    " << newPos[0] << " " << newPos[1]
         << endl;
    if (temp == INT_MIN) {
      temp = matrix[newPos[0]][newPos[1]];
      matrix[newPos[0]][newPos[1]] = matrix[pos[0]][pos[1]];
    } else {
      int buf = matrix[newPos[0]][newPos[1]];
      matrix[newPos[0]][newPos[1]] = temp;
      temp = buf;
    }
    map.insert({pos[0], pos[1]});
    pos[0] = newPos[0], pos[1] = newPos[1];
    correctPos(newPos);
  }
}

int main() {
  vector<vector<int>> matrix = {
      {1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}, {13, 14, 15, 16}};

  for (int row = 1; row <= n; row++) {
    for (int col = 1; col <= n; col++) {
      if (switched(map.begin(), map.end(), row, col)) continue;
      startPos[0] = row, startPos[1] = col;
      changePos(matrix, startPos, correctPos(startPos));
    }
  }

  for (int i = 0; i < 4; i++) {
    for (int j = 0; j < 4; j++) {
      cout << matrix[i][j] << " ";
    }
    cout << endl;
  }
  return 0;
}