在n行n列的棋盘上（如n=5），假设一位骑士（按象棋中“马走日”的行走法）从初始坐标位置(x1，y1)出发，要遍访（巡游）棋盘中的每一个位置一次。请编一个程序，为骑士求解巡游“路线图”（或告诉骑士，从某位置出发时，无法遍访整个棋盘 — 问题无解）。-In the n-n chessboard (for example, n = 5), assuming a knight (in chess in the " horse to go on"　walk method) from the initial coordinates (x1, y1) starting to visited (Parade) Each board in the first place. Please compile a program to solve for the Knight Parade " road map"　(or tell the knight, starting from a position, you can not visited the board- problem has no solution.)