update 0051.N皇后.md Go版本

problems/0051.N皇后.md

@@ -346,69 +346,56 @@ class Solution {
 
 ### Go 
 ```Go
-import "strings"
-var res [][]string
-
-func isValid(board [][]string, row, col int) (res bool){
-    n := len(board)
-    for i:=0; i < row; i++ {
-        if board[i][col] == "Q" {
-            return false
-        }
-    }
-    for i := 0; i < n; i++{
-        if board[row][i] == "Q" {
-            return false
-        }
-    }
-
-    for i ,j := row, col; i >= 0 && j >=0 ; i, j = i - 1, j- 1{
-        if board[i][j] == "Q"{
-            return false
-        }
-    }
-    for i, j := row, col; i >=0 && j < n; i,j = i-1, j+1 {
-        if board[i][j] == "Q" {
-            return false
-        }
-    }
-    return true
-}
-
-func backtrack(board [][]string, row int) {
-    size := len(board)
-    if row == size{
-        temp := make([]string, size)
-        for i := 0; i<size;i++{
-            temp[i] = strings.Join(board[i],"")
-        }
-        res =append(res,temp)
-        return 
-    }
-    for col := 0; col < size; col++ {
-        if !isValid(board, row, col){
-            continue
-        }
-        board[row][col] = "Q"
-        backtrack(board, row+1)
-        board[row][col] = "."
-    }
-}
-
 func solveNQueens(n int) [][]string {
-    res = [][]string{}
-    board := make([][]string, n)
-    for i := 0; i < n; i++{
-        board[i] = make([]string, n)
-    }
-    for i := 0; i < n; i++{
-        for j := 0; j<n;j++{
-            board[i][j] = "."
-        }
-    }
-    backtrack(board, 0)
+    var res [][]string
+	chessboard := make([][]string, n)
+	for i := 0; i < n; i++ {
+		chessboard[i] = make([]string, n)
+	}
+	for i := 0; i < n; i++ {
+		for j := 0; j < n; j++ {
+			chessboard[i][j] = "."
+		}
+	}
+	var backtrack func(int)
+	backtrack = func(row int) {
+		if row == n {
+			temp := make([]string, n)
+			for i, rowStr := range chessboard {
+				temp[i] = strings.Join(rowStr, "")
+			}
+			res = append(res, temp)
+			return
+		}
+		for i := 0; i < n; i++ {
+			if isValid(n, row, i, chessboard) {
+				chessboard[row][i] = "Q"
+				backtrack(row + 1)
+				chessboard[row][i] = "."
+			}
+		}
+	}
+	backtrack(0)
+	return res
+}
 
-    return res
+func isValid(n, row, col int, chessboard [][]string) bool {
+	for i := 0; i < row; i++ {
+		if chessboard[i][col] == "Q" {
+			return false
+		}
+	}
+	for i, j := row-1, col-1; i >= 0 && j >= 0; i, j = i-1, j-1 {
+		if chessboard[i][j] == "Q" {
+			return false
+		}
+	}
+	for i, j := row-1, col+1; i >= 0 && j < n; i, j = i-1, j+1 {
+		if chessboard[i][j] == "Q" {
+			return false
+		}
+	}
+	return true
 }
 ```
 ### Javascript