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top-100-liked/63/leetcode_test.go

@@ -0,0 +1,38 @@
+package top100liked
+
+import (
+	"fmt"
+	"testing"
+)
+
+// https://leetcode.cn/problems/search-insert-position/description/?envType=study-plan-v2&envId=top-100-liked
+
+func searchInsert(nums []int, target int) int {
+	start, end := 0, len(nums)-1
+	for start < end {
+		mid := start + (end-start)/2
+		if nums[mid] == target {
+			return mid
+		} else if nums[mid] > target {
+			end = mid - 1
+		} else {
+			start = mid + 1
+		}
+	}
+	if nums[end] < target {
+		return end + 1
+	}
+	return end
+}
+
+func Test(t *testing.T) {
+	fmt.Printf("%+v\n", searchInsert([]int{1, 3, 5, 6}, 5))
+}
+
+func Test2(t *testing.T) {
+	fmt.Printf("%+v\n", searchInsert([]int{1, 3, 5, 6}, 2))
+}
+
+func Test3(t *testing.T) {
+	fmt.Printf("%+v\n", searchInsert([]int{1, 3, 5, 6}, 7))
+}

top-100-liked/64/leetcode_test.go

@@ -0,0 +1,58 @@
+package top100liked
+
+import (
+	"fmt"
+	"testing"
+)
+
+// https://leetcode.cn/problems/search-a-2d-matrix/?envType=study-plan-v2&envId=top-100-liked
+
+// 难在边界条件
+func searchMatrix(matrix [][]int, target int) bool {
+	// 第一列竖着找
+	m := len(matrix)
+	n := len(matrix[0])
+	for i := range m {
+		cur := matrix[i][0]
+		switch {
+		case cur == target:
+			return true
+		case cur > target:
+			// target 可能在 i-1 行
+			if i-1 >= 0 {
+				for j := range n - 1 {
+					if matrix[i-1][j+1] < target {
+						continue
+					} else if matrix[i-1][j+1] == target {
+						return true
+					} else if matrix[i-1][j+1] > target {
+						return false
+					}
+				}
+			}
+		case cur < target:
+			// 如果 i == m-1 （最后一行）
+			if i == m-1 {
+				for j := range n - 1 {
+					if matrix[i][j+1] < target {
+						continue
+					} else if matrix[i][j+1] == target {
+						return true
+					} else if matrix[i][j+1] > target {
+						return false
+					}
+				}
+			}
+			continue
+		}
+	}
+	return false
+}
+
+func Test(t *testing.T) {
+	matrix := [][]int{{1, 3, 5, 7}, {10, 11, 16, 20}, {23, 30, 34, 60}}
+	target := 3
+	fmt.Println(searchMatrix(matrix, target))
+	target = 13
+	fmt.Println(searchMatrix(matrix, target))
+}

top-100-liked/65/leetcode_test.go

@@ -0,0 +1,58 @@
+package top100liked
+
+import (
+	"fmt"
+	"testing"
+)
+
+// https://leetcode.cn/problems/find-first-and-last-position-of-element-in-sorted-array/?envType=study-plan-v2&envId=top-100-liked
+
+func binarySearch(nums []int, target int) int {
+	start := 0
+	end := len(nums) - 1
+	for start <= end {
+		midIdx := start + (end-start)/2
+		mid := nums[midIdx]
+		if mid == target {
+			return midIdx
+		} else if mid > target {
+			end = midIdx - 1
+		} else if mid < target {
+			start = midIdx + 1
+		}
+	}
+	return -1
+}
+
+func searchRange(nums []int, target int) []int {
+	res := binarySearch(nums, target)
+	if res == -1 {
+		return []int{-1, -1}
+	}
+
+	l, r := res-1, res+1
+	for l >= 0 {
+		_l := binarySearch(nums[:l+1], target)
+		if _l == -1 {
+			break
+		} else {
+			l = _l - 1
+		}
+	}
+	for r < len(nums) {
+		_r := binarySearch(nums[r:], target)
+		if _r == -1 {
+			break
+		} else {
+			r = r + _r + 1
+		}
+	}
+	return []int{l + 1, r - 1}
+}
+
+func Test(t *testing.T) {
+	nums := []int{5, 7, 7, 8, 8, 10}
+	fmt.Printf("%+v\n", searchRange(nums, 8))
+	fmt.Printf("%+v\n", searchRange(nums, 6))
+	fmt.Printf("%+v\n", searchRange([]int{}, 0))
+}

top-100-liked/66/leetcode_test.go

@@ -0,0 +1,43 @@
+package top100liked
+
+import (
+	"fmt"
+	"testing"
+)
+
+// https://leetcode.cn/problems/find-minimum-in-rotated-sorted-array/?envType=study-plan-v2&envId=top-100-liked
+
+func findMin(nums []int) int {
+	if len(nums) == 1 {
+		return nums[0]
+	}
+	if nums[0] < nums[len(nums)-1] {
+		return nums[0]
+	}
+
+	start := 0
+	end := len(nums) - 1
+	for start <= end {
+		mid := start + (end-start)/2
+		if mid >= 1 && nums[mid-1] > nums[mid] && mid < len(nums)-1 && nums[mid] < nums[mid+1] {
+			return nums[mid]
+		}
+		if nums[mid] > nums[end] {
+			// 最小值在右侧
+			start = mid + 1
+		} else {
+			// 最小值在左侧
+			end = mid - 1
+		}
+	}
+	if nums[start] > nums[end] {
+		return nums[end]
+	}
+	return nums[start]
+}
+
+func Test(t *testing.T) {
+	// fmt.Println(findMin([]int{3, 4, 5, 1, 2}))
+	// fmt.Println(findMin([]int{3, 1, 2}))
+	fmt.Println(findMin([]int{2, 1}))
+}