The game of Chess has several pieces with curious movements. One of them is the Queen, which can move any number of squares in any direction: in the same line, in the same column or in any of the diagonals, as illustrated by the figure below (black dots represent positions the queen may reach in one move):
The great Chess Master Kary Gasparov invented a new type of chess problem: given the position of a queen in an empty standard chess board (that is, an 8 × 8 board) how many moves are needed so that she reaches another given square in the board?
Kary found the solution for some of those problems, but is having a difficult time to solve some others, and therefore he has asked that you write a program to solve this type of problem.
Input
The input contains several test cases. The only line of each test case contains four integers X1, Y1, X2 and Y2 (1 ≤ X1, Y1, X2, Y2 ≤ 8). The queen starts in the square with coordinates (X1, Y1), and must finish at the square with coordinates (X2, Y2). In the chessboard, columns are numbered from 1 to 8, from left ro right; lines are also numbered from 1 to 8, from top to bottom. The coordinates of a square in line X and column Y are (X, Y ).
The end of input is indicated by a line containing four zeros, separated by spaces.
Output
For each test case in the input your program must print a single line, containing an integer, indicating the smallest number of moves needed for the queen to reach the new position.
Sample Input
4 4 6 2
3 5 3 5
5 5 4 3
0 0 0 0
Sample Output
1
0
2
问题链接：UVA11494 Queen
问题简述：（略）
问题分析：
国际象棋中的后，可以走直线（包括横竖斜线），给定起始点和目标点，问需要走几步。
假设起始点为a，目标点为b，若a与b相同则0步；a与b共线则1步；其他则2步。
程序说明：（略）
参考链接：（略）
题记：（略）
AC的C++语言程序如下：
/* UVA11494 Queen */
#include <bits/stdc++.h>
using namespace std;
int main()
{
int x1, y1, x2, y2;
while ( ~scanf("%d%d%d%d", &x1, &y1, &x2, &y2) && (x1 || y1 || x2 || y2) ) {
if ( x1 == x2 && y1 == y2 )
printf("0\n");
else if( x1 == x2 || y1 == y2 || abs(x1 - x2) == abs(y1 - y2) )
printf("1\n");
else
printf("2\n");
}
return 0;
}