LeetCode051 N-Queens

来源：互联网发布：linux tomcat环境变量编辑：程序博客网时间：2024/06/01 10:11

详细见：leetcode.com/problems/n-queens

Java Solution: github

package leetcode;import java.util.LinkedList;import java.util.List;public class P051_NQueens {public static void main(String[] args) {//Queen queen = new Queen();//queen.backtrack(1);System.out.println(new Solution2().solveNQueens(8).size());}/* * 4 ms * 91.55%  */static class Solution1 {List<List<String>> ans = new LinkedList<List<String>>();int[] col = null, rup = null, lup = null, row = null;public List<List<String>> solveNQueens(int n) {if (n < 1)return ans;col = new int[n];row = new int[n];rup = new int[(n << 1) - 1];lup = new int[rup.length];search(0);return ans;}private void search(int index) {if (index == col.length) {List<String> answer = new LinkedList<String>();char[] cs = new char[index];for (int i = 0; i != index; i ++) {for (int j = 0; j != index; j ++)cs[j] = j == row[i] ? 'Q' : '.';answer.add(new String(cs));}ans.add(answer);return;}for (int i = 0; i != col.length; i ++) {if (col[i] == 0 && lup[index + i] == 0 && rup[col.length - 1 + index - i] == 0) {col[i] = lup[index + i] = rup[col.length - 1 + index - i] = 1;row[index] = i;search(index + 1);col[i] = lup[index + i] = rup[col.length - 1 + index - i] = 0;}}}}/* * 3 ms * 97.29% */static class Solution2 {List<List<String>> ans = new LinkedList<List<String>>();boolean[] col = null, rup = null, lup = null;int[] row = null;public List<List<String>> solveNQueens(int n) {if (n < 1)return ans;col = new boolean[n];row = new int[n];rup = new boolean[(n << 1) - 1];lup = new boolean[rup.length];search(0);return ans;}private void search(int index) {if (index == col.length) {List<String> answer = new LinkedList<String>();char[] cs = new char[index];for (int i = 0; i != index; i ++) {for (int j = 0; j != index; j ++)cs[j] = j == row[i] ? 'Q' : '.';answer.add(new String(cs));}ans.add(answer);return;}for (int i = 0; i != col.length; i ++) {if (! col[i] && ! lup[index + i] && ! rup[col.length - 1 + index - i]) {col[i] = lup[index + i] = rup[col.length - 1 + index - i] = true;row[index] = i;search(index + 1);col[i] = lup[index + i] = rup[col.length - 1 + index - i] = false;}}}}}

C Solution: github

/*    url: leetcode.com/problems/n-queens/    AC 6ms 16.67%    AC 3ms 50.00%*/#include <stdio.h>#include <stdlib.h>//array list starttypedef char** T;typedef struct al sal;typedef struct al * pal;struct al {    int capacity;    int size;    T* arr;};void al_expand_capacity(pal l) {    T* new_arr = (T*) malloc(sizeof(T) * (l->capacity * 2 + 1));    int i = 0;    for (i = 0; i < l->capacity; i ++)        new_arr[i] = l->arr[i];    free(l->arr);    l->arr = new_arr;    l->capacity = l->capacity * 2 + 1;}void al_add_last(pal l, T v) {    if (l->capacity == l->size) al_expand_capacity(l);    l->arr[l->size] = v;    l->size ++;}void al_add_to_index(pal l, T v, int index) {    int i = 0;    if (index > l->size) return;    if (l->capacity == l->size) al_expand_capacity(l);    for (i = l->size - 1; i >= index; i --) {        l->arr[i+1] = l->arr[i];    }    l->arr[index] = v;    l->size ++;}T* al_convert_to_array_free_l(pal l) {    T* arr = l->arr;    free(l);    return arr;}T al_access_by_index(pal l, int index) {    if (index >= l->size || index < 0) return 0;    return l->arr[index];}//array list endint valid(char** save, int i, int j, int n) {    int k = 0, ii = 0, jj = 0;    for (k = 0; k < n; k ++) {        if (k != i && save[k][j] == 'Q') return 0;        if (k != j && save[i][k] == 'Q') return 0;    }    ii = i + 1;    jj = j + 1;    while (ii < n && jj < n) {        if (save[ii][jj] != 'Q') {            ii ++;            jj ++;        } else return 0;    }    ii = i - 1;    jj = j - 1;    while (ii > -1 && jj > -1) {        if (save[ii][jj] != 'Q') {            ii --;            jj --;        } else return 0;    }    ii = i + 1;    jj = j - 1;    while (ii < n && jj > -1) {        if (save[ii][jj] != 'Q') {            ii ++;            jj --;        } else return 0;    }    ii = i - 1;    jj = j + 1;    while (ii > -1 && jj < n) {        if (save[ii][jj] != 'Q') {            ii --;            jj ++;        } else return 0;    }    return 1;}void solve(pal l, char** save, int row, int n) {    char** temp = NULL, *temp_row = NULL;    int i = 0, j = 0, col = 0;    if (row == n) {        temp = (char**) malloc(sizeof(char*) * n);;        for (i = 0; i < n; i ++) {            temp_row = (char*) malloc(sizeof(char) * (n+1));            for (j = 0; j < n; j ++) temp_row[j] = save[i][j];            temp_row[n] = '\0';            temp[i] = temp_row;        }        al_add_last(l, temp);        return;    }    for (col = 0; col < n; col ++) {        if (valid(save, row, col, n)) {            save[row][col] = 'Q';            solve(l, save, row+1, n);            save[row][col] = '.';        }    }}char*** solveNQueens(int n, int* r) {    char** save = (char**) malloc(sizeof(char*) * n);    char* save_row = NULL;    int i = 0, j = 0;    pal l = (pal) malloc(sizeof(sal));    l->size = 0;    l->capacity = 16;    l->arr = (T*) malloc(sizeof(T) * l->capacity);    for (i = 0; i < n; i ++) {        save_row = (char*) malloc(sizeof(char) * (n+1));        for (j = 0; j < n; j ++) save_row[j] = '.';        save_row[n] = '\0';        save[i] = save_row;    }    solve(l, save, 0, n);    *r = l->size;    return al_convert_to_array_free_l(l);}void solve2(pal l, char** save, int row, int n, int* col_sign, int* lup_sign, int* rup_sign) {    char** temp = NULL, *temp_row = NULL;    int i = 0, j = 0, col = 0;    if (row == n) {        temp = (char**) malloc(sizeof(char*) * n);;        for (i = 0; i < n; i ++) {            temp_row = (char*) malloc(sizeof(char) * (n+1));            for (j = 0; j < n; j ++) temp_row[j] = save[i][j];            temp_row[n] = '\0';            temp[i] = temp_row;        }        al_add_last(l, temp);        return;    }    for (col = 0; col < n; col ++) {        if (!col_sign[col] && !lup_sign[col - row + n - 1] && !rup_sign[row + col]) {            col_sign[col] = lup_sign[col - row + n - 1] = rup_sign[row + col] = 1;            save[row][col] = 'Q';            solve2(l, save, row+1, n, col_sign, lup_sign, rup_sign);            save[row][col] = '.';            col_sign[col] = lup_sign[col - row + n - 1] = rup_sign[row + col] = 0;        }    }}char*** solveNQueens2(int n, int* r) {    char** save = (char**) malloc(sizeof(char*) * n);    char* save_row = NULL;    int i = 0, j = 0;    pal l = (pal) malloc(sizeof(sal));    int *col_sign = NULL, *lup_sign = NULL, *rup_sign = NULL;     l->size = 0;    l->capacity = 16;    l->arr = (T*) malloc(sizeof(T) * l->capacity);    col_sign = (int*) malloc(sizeof(int) * n);    lup_sign = (int*) malloc(sizeof(int) * (2 * n - 1));    rup_sign = (int*) malloc(sizeof(int) * (2 * n - 1));    for (i = 0; i < n; i ++) col_sign[i] = 0;    for (i = 0; i < 2 * n - 1; i ++) lup_sign[i] = 0;    for (i = 0; i < 2 * n - 1; i ++) rup_sign[i] = 0;    for (i = 0; i < n; i ++) {        save_row = (char*) malloc(sizeof(char) * (n+1));        for (j = 0; j < n; j ++) save_row[j] = '.';        save_row[n] = '\0';        save[i] = save_row;    }    solve2(l, save, 0, n, col_sign, lup_sign, rup_sign);    *r = l->size;    free(col_sign);    free(lup_sign);    free(rup_sign);    return al_convert_to_array_free_l(l);}int main() {    int r = 0;    int n = 13;    int i = 0;    int j = 0;    char*** ans = NULL;    for (n = 1; n < 7; n ++) {        ans = solveNQueens2(n, &r);                    printf("n is %d  r is %d\r\n", n, r);        for (i = 0; i < r; i ++) {            for (j = 0; j < n; j ++) {                printf("%s\r\n", ans[i][j]);                free(ans[i][j]);            }            printf("=======================\r\n");        }        free(ans);    }}

Python Solution: github

#coding=utf-8'''    url: leetcode.com/problems/n-queens    @author:     zxwtry    @email:      zxwtry@qq.com    @date:       2017年4月9日    @details:    Solution: 92ms 83.33%'''class Solution(object):    def search(self, a, c, l, r, i, n, rec):        if i == n:            a_t,a_j=[],['.']*8            for j in range(n):                for j in range(n):                    a_j[j]=(rec[j][j])                a_t.append("".join(a_j))            a.append(a_t)            return        for j in range(n):            if not c[j] and not l[j+i] and not r[j-i+n-1]:                c[j]=l[j+i]=r[j-i+n-1]=True                rec[i][j]='Q'                self.search(a, c, l, r, i+1, n, rec)                c[j]=l[j+i]=r[j-i+n-1]=False                rec[i][j]='.'                    def solveNQueens(self, n):        """        :type n: int        :rtype: List[List[str]]        """        a,c,l,r=[],[False]*n,[False]*(2*n-1),[False]*(2*n-1)        rec=[['.' for i in range(n)] for j in range(n)]        self.search(a, c, l, r, 0, n, rec)        return aif __name__ == "__main__":    print(Solution().solveNQueens(5))

0 0