poj-2488 A Knight's Journey

#include<stdio.h>#include<stdlib.h>#include<math.h>#include<string.h>int map[50][50];int p, q;int move[8][2] = {-1, -2, 1, -2, -2, -1, 2, -1, -2, 1, 2, 1, -1, 2, 1, 2};int pn[50];char qn[50];int flag;void dfs(int num, char ch, int step) {int i;if(step == p * q) {flag = 1;int k;for(k = 0; k < step; k++) {printf("%c%d", qn[k], pn[k]);}printf("\n");return;}for(i = 0; i < 8; i++) {int tnum = num + move[i][0];char tch = ch + move[i][1];if(tnum < 0 || tch < 'A' || tnum >= p || tch >= 'A' + q || map[tnum][tch - 'A'] == 1 || flag) {continue;}else {map[tnum][tch - 'A'] = 1;pn[step] = tnum + 1;qn[step] = tch;dfs(tnum, tch, step + 1);map[tnum][tch - 'A'] = 0;}}}int main() {int n;scanf("%d", &n);int count = 0;while(n--) {scanf("%d %d", &p, &q);flag = 0;memset(map, 0, sizeof(map));printf("Scenario #%d:\n", ++count);map[0][0] = 1;pn[0] = 1;qn[0] = 'A';dfs(0, 'A', 1);if(!flag) printf("impossible\n");printf("\n");}return 0;}