feat: 最小覆盖子串

Author: sl1673495

无重复字符的最长子串（滑动窗口）.js

@@ -0,0 +1,49 @@
+/**
+ * @param {string} s
+ * @param {string} p
+ * @return {number[]}
+ */
+let findAnagrams = function (s, p) {
+  let sl = s.length
+  let pl = p.length
+  let last = sl - pl + 1
+
+  let res = []
+  for (let i = 0; i < last; i++) {
+    if (isAnagrams(s, p, i)) {
+      res.push(i)
+    }
+  }
+
+  return res
+}
+
+let isAnagrams = function (s, p, start) {
+  let pl = p.length
+  let end = start + pl
+
+  let sub = s.substring(start, end)
+  let subMap = {}
+  let pMap = {}
+
+  countStr(sub, subMap)
+  countStr(p, pMap)
+
+  let subKeys = Object.keys(subMap)
+  for (let subKey of subKeys) {
+    if (!pMap[subKey] || subMap[subKey] !== pMap[subKey]) {
+      return false
+    }
+  }
+  return true
+
+  function countStr(str, map) {
+    for (let i = 0; i < str.length; i++) {
+      if (!map[str[i]]) {
+        map[str[i]] = 1
+      } else {
+        map[str[i]]++
+      }
+    }
+  }
+}

滑动窗口/找到字符串中所有字母异位词-438.js

@@ -0,0 +1,28 @@
+/**
+ * @param {string} s
+ * @return {number}
+ */
+let lengthOfLongestSubstring = function (str) {
+  let n = str.length
+  // 滑动窗口为s[left...right]
+  let left = 0
+  let right = -1
+  let freqMap = {} // 记录当前子串中下标对应的出现频率
+  let max = 0 // 找到的满足条件子串的最长长度
+
+  while (left < n) {
+    let nextLetter = str[right + 1]
+    if (!freqMap[nextLetter] && nextLetter !== undefined) {
+      freqMap[nextLetter] = 1
+      right++
+    } else {
+      freqMap[str[left]] = 0
+      left++
+    }
+    max = Math.max(max, right - left + 1)
+  }
+
+  return max
+}
+
+console.log(lengthOfLongestSubstring("pwwkew"))

滑动窗口/无重复字符的最长子串-3.js

@@ -0,0 +1,60 @@
+/**
+ * @param {string} s
+ * @param {string} t
+ * @return {string}
+ */
+let minWindow = function (s, t) {
+  // 先制定目标 根据t字符串统计出每个字符应该出现的个数
+  let targetMap = makeCountMap(t)
+
+  let sl = s.length
+  let left = 0
+  let right = -1
+  let countMap = {}
+  let min = ""
+
+  while (left <= sl && right <= sl) {
+    let isValid = true
+    Object.keys(targetMap).forEach((key) => {
+      let targetCount = targetMap[key]
+      let count = countMap[key]
+      if (!count || count < targetCount) {
+        isValid = false
+      }
+    })
+
+    if (isValid) {
+      let currentValidLength = right - left + 1
+      if (currentValidLength < min.length || min === "") {
+        min = s.substring(left, right + 1)
+      }
+      // 也要把map里对应的项去掉
+      countMap[s[left]]--
+      left++
+    } else {
+      addCountToMap(countMap, s[right + 1])
+      right++
+    }
+  }
+
+  return min
+}
+
+function addCountToMap(map, str) {
+  if (!map[str]) {
+    map[str] = 1
+  } else {
+    map[str]++
+  }
+}
+
+function makeCountMap(strs) {
+  let map = {}
+  for (let i = 0; i < strs.length; i++) {
+    let letter = strs[i]
+    addCountToMap(map, letter)
+  }
+  return map
+}
+
+console.log(minWindow("ADOBECODEBANC", "ABC"))