...
| Code Block |
|---|
|
type NumMatrix struct {
sums [][]int
}
func Constructor(matrix [][]int) NumMatrix {
sums := make([][]int, len(matrix)+1)
sums[0] = make([]int, len(matrix[0])+1)
for i := range matrix {
sums[i+1] = make([]int, len(matrix[0])+1)
for j := range matrix[i] {
sums[i+1][j+1] = sums[i+1][j] + matrix[i][j]
}
}
// fmt.Println(sums)
for i := range matrix {
for j := range matrix[i] {
sums[i+1][j+1] += sums[i][j+1]
}
}
// for i := range sums {
// for j := range sums[i] {
// fmt.Printf("%2d ", sums[i][j])
// }
// fmt.Println()
// }
return NumMatrix { sums }
}
func (this *NumMatrix) SumRegion(row1 int, col1 int, row2 int, col2 int) int {
return this.sums[row2+1][col2+1] - this.sums[row1][col2+1] - this.sums[row2+1][col1] + this.sums[row1][col1]
}
/**
* Your NumMatrix object will be instantiated and called as such:
* obj := Constructor(matrix);
* param_1 := obj.SumRegion(row1,col1,row2,col2);
*/ |
双指针数组
LC 88. Merge Sorted Array 合并两个有序数组
https://leetcode.com/problems/merge-sorted-array/ & More
| Code Block |
|---|
|
func merge(nums1 []int, m int, nums2 []int, n int) {
i, j := m-1, n-1
p := m+n-1
for i >= 0 && j >= 0 {
if nums1[i] >= nums2[j] {
nums1[p] = nums1[i]
p--
i--
} else {
nums1[p] = nums2[j]
p--
j--
}
}
for i >= 0 {
nums1[p] = nums1[i]
p--
i--
}
for j >= 0 {
nums1[p] = nums2[j]
p--
j--
}
} |
LC 977. Squares of a Sorted Array 有序数组的平方
https://leetcode.com/problems/squares-of-a-sorted-array/description/
| Code Block |
|---|
|
func sortedSquares(nums []int) []int {
n := len(nums)
i, j := 0, n-1
result := make([]int, n)
p := n-1
for i <= j {
a := nums[i] * nums[i]
b := nums[j] * nums[j]
if a >= b {
result[p] = a
p--
i++
} else {
result[p] = b
p--
j--
}
}
return result
} |
LC 360. 有序转化数组 [Premium]
https://leetcode.com/problems/sort-transformed-array/description/
LC 1329. 将矩阵按对角线排序
https://leetcode.com/problems/sort-the-matrix-diagonally/description/
– 剩下 2 题