回溯法 8皇后

问题太经典，就不描述问题了：

public class HuangHou8 {static int n=8;static int tot=0;static int[] C;static int[][] vis=new int[3][16];public static void main(String[] args) {tot=0;C=new int[8];search(0);System.out.println(tot);tot=0;C=new int[8];search2(0);System.out.println(tot);}public static void search(int cur){if(cur==n){tot++;for (int i = 0; i < C.length; i++) {System.out.print(C[i]+"  ");}System.out.println();}else{for (int i = 0; i < n; i++) {int ok=1;C[cur]=i;for (int j = 0; j < cur; j++) {if(C[cur]==C[j]||cur-C[cur]==j-C[j]||cur+C[cur]==j+C[j]){ok=0;break;}}if(ok==1){search(cur+1);}}}}public static void search2(int cur){if(cur==n){tot++;}else{for (int i = 0; i < n; i++) {if(vis[0][i]==0&&vis[1][cur+i]==0&&vis[2][cur-i+n]==0){C[cur]=i;vis[0][i]=vis[1][cur+i]=vis[2][cur-i+n]=1;search2(cur+1);vis[0][i]=vis[1][cur+i]=vis[2][cur-i+n]=0;}}}}}