sicily 1152 1153 马的周游

之前发过一篇1152的，后来做1153发现找不到一条回路。。郁闷，只好循规蹈矩。

思路：

1.深搜，无优化，TL；

2.加上对每次游走时的分析，先走入度较小的点，我认为这样可以快速排除不能走的点。

#include <iostream>#include <cstring>#include <map>using namespace std;//#define COL 6//#define ROW 5#define COL 8#define ROW 8int n;int path[COL * ROW];int move[8][2] = {{1, 2}, {1, -2}, {-1, 2}, {-1, -2}, {2, 1}, {2, -1}, {-2, 1}, {-2, -1}};int cur;int num[ROW][COL];bool isVis[ROW][COL];int degree[ROW][COL];int degreeTmp[ROW][COL];bool dfs() {if(cur == ROW * COL - 1) return true;int x = (path[cur] - 1) / COL;int y = (path[cur] - 1) % COL;multimap<int, int> suitNext;for(int i = 0; i < 8; i++) {int next_x = x + move[i][0];int next_y = y + move[i][1];if(next_x >= 0 && next_x < ROW && next_y >= 0 && next_y < COL && !isVis[next_x][next_y]) {degreeTmp[next_x][next_y]--;suitNext.insert(make_pair(degreeTmp[next_x][next_y], i));}}for(multimap<int, int>::iterator iter = suitNext.begin();iter != suitNext.end(); iter++) {int next_x = x + move[iter->second][0];int next_y = y + move[iter->second][1];isVis[next_x][next_y] = true;path[++cur] = num[next_x][next_y];if(dfs()) return true;isVis[next_x][next_y] = false;cur--;degreeTmp[next_x][next_y]++;}return false;}void setNUM() {int a = 1;for(int i = 0; i < ROW; i++) {for(int j = 0; j < COL; j++) {num[i][j] = a++;}}}void setDegree() {memset(degree, 0, sizeof(degree));for(int i = 0; i < ROW; i++) {for(int j = 0; j < COL; j++) {for(int k = 0; k < 8; k++) {int next_x = i + move[k][0];int next_y = j + move[k][1];if(next_x >= 0 && next_x < ROW && next_y >= 0 && next_y < COL)degree[next_x][next_y]++;}}}}int main() {setNUM();setDegree();while(cin >> n && n != -1) {path[0] = n;cur = 0;memset(isVis, false, sizeof(isVis));memcpy(degreeTmp, degree, sizeof(degree));isVis[(n - 1) / COL][(n - 1) % COL] = true;dfs();bool isFirst = true;for(int i = 0; i < COL * ROW; i++) {if(isFirst) {cout << path[i];isFirst = false;}else cout << " " << path[i];}cout << endl;}return 0;}