From 827cc69b7141a7dedfa2c4363c5d827d81383c47 Mon Sep 17 00:00:00 2001
From: jerryfishcode <91447694+jerryfishcode@users.noreply.github.com>
Date: Tue, 28 Sep 2021 12:29:50 +0800
Subject: [PATCH] =?UTF-8?q?=E6=96=B0=E5=A2=9E52.=20N=E7=9A=87=E5=90=8E=20I?=
 =?UTF-8?q?I=20JavaScript=E7=89=88=E6=9C=AC?=
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---
 problems/0052.N皇后II.md | 44 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)

diff --git a/problems/0052.N皇后II.md b/problems/0052.N皇后II.md
index 1a34f763..d7d7feb8 100644
--- a/problems/0052.N皇后II.md
+++ b/problems/0052.N皇后II.md
@@ -101,4 +101,48 @@ public:
 ```
 
 # 其他语言补充
+JavaScript
+```javascript
+var totalNQueens = function(n) {
+    let count = 0;
+    const backtracking = (n, row, chessboard) => {
+        if(row === n){
+            count++;
+            return;
+        }
+        for(let col = 0; col < n; col++){
+            if(isValid(row, col, chessboard, n)) { // 验证合法就可以放
+                chessboard[row][col] = 'Q'; // 放置皇后
+                backtracking(n, row + 1, chessboard);
+                chessboard[row][col] = '.'; // 回溯
+            }
+        }
+    }
 
+    const isValid = (row, col, chessboard, n) => {
+        // 检查列
+        for(let i = 0; i < row; i++){ // 这是一个剪枝
+            if(chessboard[i][col] === 'Q'){
+                return false;
+            }
+        }
+        // 检查 45度角是否有皇后
+        for(let i = row - 1, j = col - 1; i >= 0 && j >= 0; i--, j--){
+            if(chessboard[i][j] === 'Q'){
+                return false;
+            }
+        }
+        // 检查 135度角是否有皇后
+        for(let i = row - 1, j = col + 1; i >= 0 && j < n; i--, j++){
+            if(chessboard[i][j] === 'Q'){
+                return false;
+            }
+        }
+        return true;
+    }
+
+    const chessboard = new Array(n).fill([]).map(() => new Array(n).fill('.'));
+    backtracking(n, 0, chessboard);
+    return count;
+};
+```