1
func generateMatrix(n int) [][]int {
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    matrix := make([][]int, n)
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    count := 0
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    circle := 0
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    len := n
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    square := n*n
7

8
    for i := 0; i < n; i++{
9
        matrix[i] = make([]int, n)
10
    }
11

12
    for count < square {
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        for i := 0; i < n; i++ {
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            count++
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            matrix[circle][i+circle] = count
16
        }
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        for i := 1; i < n; i++ {
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            count++
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            matrix[i+circle][len-circle-1] = count
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        }
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23
        for i := len-circle-2; i >= circle; i-- {
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            count++
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            matrix[len-circle-1][i] = count
26
        }
27

28
        for i := len-circle-2; i >= circle+1; i-- {
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            count++
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            matrix[i][circle] = count
31
        }
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        n -= 2
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        circle++
35
    }
36

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    return matrix
38
}

1
func generateMatrix(n int) [][]int {
2
    matrix := make([][]int, n)
3
    for i := 0; i < n; i++ {
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        matrix[i] = make([]int, n)
5
    }
6

7
    top, bottom := 0, n-1
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    left, right := 0, n-1
9

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    count := 1
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    target := n * n
12

13
    for count <= target {
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        // 1. 从左到右（贴着 top 走），走完后 top 边界下移
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        for i := left; i <= right; i++ {
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            matrix[top][i] = count
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            count++
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        }
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        top++
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        // 2. 从上到下（贴着 right 走），走完后 right 边界左移
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        for i := top; i <= bottom; i++ {
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            matrix[i][right] = count
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            count++
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        }
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        right--
27

28
        // 3. 从右到左（贴着 bottom 走），走完后 bottom 边界上移
29
        for i := right; i >= left; i-- {
30
            matrix[bottom][i] = count
31
            count++
32
        }
33
        bottom--
34

35
        // 4. 从下到上（贴着 left 走），走完后 left 边界右移
36
        for i := bottom; i >= top; i-- {
37
            matrix[i][left] = count
38
            count++
39
        }
40
        left++
41
    }
42

43
    return matrix
44
}