✨ Add solution and test-cases for Problem 51

Author: Cori1109

leetcode/1-100/0051.N-Queens/Solution.go

@@ -1,5 +1,53 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+import "strings"
+
+func Solution(x int) [][]string {
+	board := make([][]string, x)
+	for i := range board {
+		board[i] = make([]string, x)
+		for j := range board[i] {
+			board[i][j] = ".";
+		}
+	}
+	res := make([][]string, 0)
+	helper(board, &res, 0);
+	return res
+}
+
+func helper(board [][]string, res *[][]string, row int) {
+	if len(board) == row {
+		temp := make([]string, 0);
+		for i := range board {
+			temp = append(temp, strings.Join(board[i], ""));
+		}
+		*res = append(*res, temp);
+		return;
+	}
+	for col := 0; col < len(board); col++ {
+		if isValid(board, row, col) {
+			board[row][col] = "Q";
+			helper(board, res, row + 1);
+			board[row][col] = ".";
+		}
+	}
+}
+
+func isValid(board [][]string, r , c int) bool {
+	for i := 0; i < r; i++ {
+		if board[i][c] == "Q" {
+			return false;
+		}
+	}
+	for i, j := r, c; i >= 0 && j >= 0; i, j = i - 1, j - 1 {
+		if board[i][j] == "Q" {
+			return false;
+		}
+	}
+	for i, j := r, c; i >= 0 && j < len(board); i, j = i - 1, j + 1 {
+		if board[i][j] == "Q" {
+			return false;
+		}
+	}
+	return true;
 }

leetcode/1-100/0051.N-Queens/Solution_test.go

@@ -9,21 +9,20 @@ func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
 		name   string
-		inputs bool
-		expect bool
+		x int
+		expect [][]string
 	}{
-		{"TestCacse 1", true, true},
-		{"TestCacse 1", true, true},
-		{"TestCacse 1", false, false},
+		{"TestCase", 4, [][]string{{".Q..","...Q","Q...","..Q."},{"..Q.","Q...","...Q",".Q.."}}},
+		{"TestCase", 1, [][]string{{"Q"}}},
 	}
 
 	//	开始测试
 	for _, c := range cases {
 		t.Run(c.name, func(t *testing.T) {
-			ret := Solution(c.inputs)
+			ret := Solution(c.x)
 			if !reflect.DeepEqual(ret, c.expect) {
 				t.Fatalf("expected: %v, but got: %v, with inputs: %v",
-					c.expect, ret, c.inputs)
+					c.expect, ret, c.x)
 			}
 		})
 	}

leetcode/1-100/0051.n-queens.md

@@ -2,25 +2,27 @@
 
 ## Description
 
-Given two binary strings, return their sum \(also a binary string\).
+The **n-queens** puzzle is the problem of placing `n` queens on an `n` x `n` chessboard such that no two queens attack each other.
 
-The input strings are both **non-empty** and contains only characters `1` or `0`.
+Given an integer `n`, return all distinct solutions to the **n-queens puzzle**. You may return the answer in **any order**.
+
+Each solution contains a distinct board configuration of the n-queens' placement, where `'Q'` and `'.'` both indicate a queen and an empty space, respectively.
 
 **Example 1:**
 
 ```text
-Input: a = "11", b = "1"
-Output: "100"
+Input: n = 4
+Output: [[".Q..","...Q","Q...","..Q."],["..Q.","Q...","...Q",".Q.."]]
 ```
 
 **Example 2:**
 
 ```text
-Input: a = "1010", b = "1011"
-Output: "10101"
+Input: n = 1
+Output: [["Q"]]
 ```
 
-**Tags:** Math, String
+**Tags:** Array, Backtracking
 
 ## 题意