为什么运算符不给出不同的结果而是使用 = 给出正确的答案

Question

 static int count = 0;

  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    count = 0;
    int n = sc.nextInt();
    int arr[][] = new int[n][n];
    for (int i = 0; i < n; i++) {
      for (int j = 0; j < n; j++) {
        arr[i][j] = sc.nextInt();
      }
    }
    for (int i = 0; i < n ; i++) {
      row(arr, n, i);
      column(arr, n, i);
    }
    System.out.println(count);
    for (int i = 0; i < n; i++) {
      for (int j = 0; j < n; j++) {
        System.out.print(arr[i][j] + " ");
      }
    }
  }

  static void row(int arr[][], int n, int row) {
    int x, y, min, yHold = 0;

    for (x = 0; x < n; x++) {
      boolean yes = false;
      min = arr[row][x];

      for (y = row; y < n; y++) {
        if (arr[y][x] < min) {
          min = arr[y][x];
          yHold = y;
          yes = true;
        }
      }
      if (yes) {
        int temp = arr[row][x];
        arr[row][x] = min;
        arr[yHold][x] = temp;
        count++;
      }
    }

If I replace yes=true with yes=!yes , the output becomes different. Please help, can't seem to figure it out. The part of the problem the function row is taking are of is:

If we are at ith row, then we have to work with each column at a time from 0 to n−1 of this row. For any jth column, swap A[i][j] with the minimum of all the elements which are present in a column with index j and rows from indices i to n−1.

Answer 1

The problem is that the statement can be executed multiple times. In the case of yes = true , the result will always be that yes becomes true . But with yes = !yes , the result is that yes will flip flop between true and false .

Answer 2

When you say yes = true , it is always going to be true. But when you say, yes = !yes it will flip back and forth between true and false.

boolean yes = true;
for (int i = i < 10; i++) {
 System.out.println(yes);   
 yes =! yes;
}

prints

true
false
true
false
true
false
true
false
true
false