Merge pull request #197 from lightfish-zhang/master

 add Solution for problem 34, 153, 241, wtih golang

Author: yanglbme

solution/0034.Find First and Last Position of Element in Sorted Array/Solution.go

@@ -0,0 +1,48 @@
+/**
+ * @lc app=leetcode.cn id=34 lang=golang
+ * Accepted
+ * 88/88 cases passed (12 ms)
+ * Your runtime beats 90.75 % of golang submissions
+ * Your memory usage beats 60.76 % of golang submissions (4.1 MB)
+ */
+func searchRange(nums []int, target int) []int {
+	l, m, r := 0, 0, len(nums)-1
+	for l <= r {
+		m = (l + r) / 2
+		if nums[m] == target {
+			return []int{findFirst(nums, l, m, target), findEnd(nums, m, r, target)}
+		}
+		if nums[m] < target {
+			l = m + 1
+		} else if nums[m] > target {
+			r = m - 1
+		}
+	}
+	return []int{-1, -1}
+}
+
+func findFirst(nums []int, l, r, target int) int {
+	var m int
+	for l < r {
+		m = (l + r) / 2
+		if nums[m] < target {
+			l = m + 1
+		} else if nums[m] == target {
+			r = m
+		}
+	}
+	return l
+}
+func findEnd(nums []int, l, r, target int) int {
+	var m int
+	for l < r {
+		m = (l + r + 1) / 2 // 需要加一，否则陷入死循环
+		if nums[m] > target {
+			r = m - 1
+		} else if nums[m] == target {
+			l = m
+		}
+	}
+	return l
+}
+

solution/0153.Find Minimum in Rotated Sorted Array/Solution.go

@@ -0,0 +1,23 @@
+/**
+ * @lc app=leetcode.cn id=153 lang=golang
+ * Accepted
+ * 146/146 cases passed (4 ms)
+ * Your runtime beats 93 % of golang submissions
+ * Your memory usage beats 40.91 % of golang submissions (2.6 MB)
+ */
+func findMin(nums []int) int {
+	l, m, r := 0, 0, len(nums)-1
+	for l < r {
+		if nums[l] <= nums[r] {
+			return nums[l]
+		}
+		m = (r + l) / 2
+		if nums[l] <= nums[m] {
+			l = m + 1
+		} else {
+			r = m
+		}
+
+	}
+	return nums[l]
+}

solution/0241.Different Ways to Add Parentheses/Solution.go

@@ -0,0 +1,36 @@
+/**
+ * @lc app=leetcode.cn id=241 lang=golang
+ * Accepted
+ * 25/25 cases passed (4 ms)
+ * Your runtime beats 52.94 % of golang submissions
+ * Your memory usage beats 100 % of golang submissions (6.5 MB)
+ * time complex O(n^2)
+ */
+
+import "strconv"
+
+func diffWaysToCompute(input string) []int {
+	ret := []int{}
+	for i, c := range input {
+		if c == '+' || c == '-' || c == '*' {
+			left_ret := diffWaysToCompute(input[0:i])
+			right_ret := diffWaysToCompute(input[i+1:])
+			for _, l_ret := range left_ret {
+				for _, r_ret := range right_ret {
+					if c == '+' {
+						ret = append(ret, l_ret+r_ret)
+					} else if c == '-' {
+						ret = append(ret, l_ret-r_ret)
+					} else {
+						ret = append(ret, l_ret*r_ret)
+					}
+				}
+			}
+		}
+	}
+	if len(ret) == 0 {
+		num, _ := strconv.Atoi(input)
+		ret = append(ret, num)
+	}
+	return ret
+}