简单难度

Author: marchanbbb

193.有效电话号码.go

@@ -0,0 +1,31 @@
+/*
+ * @lc app=leetcode.cn id=204 lang=golang
+ *
+ * [204] 计数质数
+ */
+
+// @lc code=start
+func countPrimes(n int) int {
+	if n < 3 {
+		return 0
+	}
+	res := 1
+	for i:=3; i<n; i++{
+		if i & 1 == 0 {
+			continue
+		}
+		sign := true
+		for j:=3; j*j<=i; j+=2 {
+			if i%j == 0 {
+				sign = false
+				break
+			}
+		}
+		if sign {
+			res++
+		}
+	}
+	return res
+}
+// @lc code=end
+

204.计数质数.go

@@ -0,0 +1,21 @@
+/*
+ * @lc app=leetcode.cn id=205 lang=golang
+ *
+ * [205] 同构字符串
+ */
+
+// @lc code=start
+func isIsomorphic(s string, t string) bool {
+	s2t,t2s := map[byte]byte{}, map[byte]byte{}
+	for i := range s {
+        x, y := s[i], t[i]
+        if s2t[x] > 0 && s2t[x] != y || t2s[y] > 0 && t2s[y] != x {
+            return false
+        }
+        s2t[x] = y
+        t2s[y] = x
+    }
+	return true
+}
+// @lc code=end
+

205.同构字符串.go

@@ -0,0 +1,19 @@
+/*
+ * @lc app=leetcode.cn id=217 lang=golang
+ *
+ * [217] 存在重复元素
+ */
+
+// @lc code=start
+func containsDuplicate(nums []int) bool {
+  numsM := map[int]bool{}
+  for _, i := range nums {
+	  if numsM[i] == true {
+		  return true
+	  }
+	  numsM[i] = true
+  }
+  return false
+}
+// @lc code=end
+

217.存在重复元素.go

@@ -0,0 +1,24 @@
+/*
+ * @lc app=leetcode.cn id=219 lang=golang
+ *
+ * [219] 存在重复元素 II
+ */
+
+// @lc code=start
+func containsNearbyDuplicate(nums []int, k int) bool {
+	l := len(nums)
+	numsM := make(map[int]int, l)
+	for i := 0; i < l; i++ {
+		n := nums[i]
+		if numsM[n] > 0 {
+			if j := i - numsM[n] + 1; j <= k {
+				return true
+			}
+		}
+		numsM[n] = i + 1
+	}
+	return false
+}
+
+// @lc code=end
+

219.存在重复元素-ii.go

@@ -0,0 +1,38 @@
+/*
+ * @lc app=leetcode.cn id=41 lang=golang
+ *
+ * [41] 缺失的第一个正数
+ */
+
+// @lc code=start
+func firstMissingPositive(nums []int) int {
+	l := len(nums)
+	if l == 0 {
+		return 1
+	}
+	for i := 0; i < l; i++ {
+		if nums[i] <= 0 {
+			nums[i] = l + 1
+		}
+	}
+	for i := 0; i < l; i++ {
+		j := nums[i]
+		if j < 0 {
+			j = j * -1
+		}
+		if j > 0 && j <= l {
+			if nums[j-1] > 0 {
+				nums[j-1] = -nums[j-1]
+			}
+		}
+	}
+	for i, n := range nums {
+		if n > 0 {
+			return i + 1
+		}
+	}
+	return l + 1
+}
+
+// @lc code=end
+