<qiyuangong>367_Valid_Perfect_Square_1.java
public boolean isPerfectSquare(int num) {
        int low = 1;
        int high = num;
        while (low <= high) {
            long mid = (low + high) >>> 1;
            if (mid * mid == num) {
                return true;
            } else if (mid * mid < num) {
                low = (int) mid + 1;
            } else {
                high = (int) mid - 1;
            }
        }
        return false;
    }
public boolean var_0 ( int var_1 ) {
  int var_3 = 1 ;
  int var_4 = var_1 ;
  while ( var_3 <= var_4 ) {
    long var_5 = ( var_3 + var_4 ) >>> 1 ;
    if ( var_5 * var_5 == var_1 ) {
      return true ;
    }
    else if ( var_5 * var_5 < var_1 ) {
      var_3 = ( int ) var_5 + 1 ;
    }
    else {
      var_4 = ( int ) var_5 - 1 ;
    }
  }
  return false ;
}
