feat: add solutions to lc problem: No.691 (doocs#2898)

No.0691.Stickers to Spell Word

Author: yanglbme

solution/0600-0699/0691.Stickers to Spell Word/README.md

@@ -69,30 +69,36 @@ tags:
 
 ### 方法一：BFS + 状态压缩
 
+我们注意到，字符串 $\text{target}$ 的长度不超过 $15$，我们可以使用一个长度为 $15$ 的二进制数来表示 $\text{target}$ 的每个字符是否被拼出，如果第 $i$ 位为 $1$，表示 $\text{target}$ 的第 $i$ 个字符已经被拼出，否则表示未被拼出。
+
+我们定义一个初始状态 $0$，表示所有字符都未被拼出，然后我们使用广度优先搜索的方法，从初始状态开始，每次搜索时，我们枚举所有的贴纸，对于每一张贴纸，我们尝试拼出 $\text{target}$ 的每一个字符，如果拼出了某个字符，我们就将对应的二进制数的第 $i$ 位设置为 $1$，表示该字符已经被拼出，然后我们继续搜索，直到我们拼出了 $\text{target}$ 的所有字符。
+
+时间复杂度 $O(2^n \times m \times (l + n))$，空间复杂度 $O(2^n)$。其中 $n$ 是字符串 $\text{target}$ 的长度，而 $m$ 和 $l$ 分别是贴纸的数量和贴纸的平均长度。
+
 <!-- tabs:start -->
 
 #### Python3
 
 ```python
 class Solution:
     def minStickers(self, stickers: List[str], target: str) -> int:
-        q = deque([0])
-        ans = 0
         n = len(target)
+        q = deque([0])
         vis = [False] * (1 << n)
         vis[0] = True
+        ans = 0
         while q:
             for _ in range(len(q)):
-                state = q.popleft()
-                if state == (1 << n) - 1:
+                cur = q.popleft()
+                if cur == (1 << n) - 1:
                     return ans
                 for s in stickers:
-                    nxt = state
                     cnt = Counter(s)
+                    nxt = cur
                     for i, c in enumerate(target):
-                        if not (nxt & (1 << i)) and cnt[c]:
-                            nxt |= 1 << i
+                        if (cur >> i & 1) == 0 and cnt[c] > 0:
                             cnt[c] -= 1
+                            nxt |= 1 << i
                     if not vis[nxt]:
                         vis[nxt] = True
                         q.append(nxt)
@@ -105,29 +111,28 @@ class Solution:
 ```java
 class Solution {
     public int minStickers(String[] stickers, String target) {
+        int n = target.length();
         Deque<Integer> q = new ArrayDeque<>();
         q.offer(0);
-        int ans = 0;
-        int n = target.length();
         boolean[] vis = new boolean[1 << n];
         vis[0] = true;
-        while (!q.isEmpty()) {
-            for (int t = q.size(); t > 0; --t) {
-                int state = q.poll();
-                if (state == (1 << n) - 1) {
+        for (int ans = 0; !q.isEmpty(); ++ans) {
+            for (int m = q.size(); m > 0; --m) {
+                int cur = q.poll();
+                if (cur == (1 << n) - 1) {
                     return ans;
                 }
                 for (String s : stickers) {
-                    int nxt = state;
                     int[] cnt = new int[26];
+                    int nxt = cur;
                     for (char c : s.toCharArray()) {
                         ++cnt[c - 'a'];
                     }
                     for (int i = 0; i < n; ++i) {
-                        int idx = target.charAt(i) - 'a';
-                        if ((nxt & (1 << i)) == 0 && cnt[idx] > 0) {
+                        int j = target.charAt(i) - 'a';
+                        if ((cur >> i & 1) == 0 && cnt[j] > 0) {
+                            --cnt[j];
                             nxt |= 1 << i;
-                            --cnt[idx];
                         }
                     }
                     if (!vis[nxt]) {
@@ -136,7 +141,6 @@ class Solution {
                     }
                 }
             }
-            ++ans;
         }
         return -1;
     }
@@ -149,25 +153,28 @@ class Solution {
 class Solution {
 public:
     int minStickers(vector<string>& stickers, string target) {
-        queue<int> q{{0}};
-        int ans = 0;
         int n = target.size();
+        queue<int> q{{0}};
         vector<bool> vis(1 << n);
         vis[0] = true;
-        while (!q.empty()) {
-            for (int t = q.size(); t; --t) {
-                int state = q.front();
-                if (state == (1 << n) - 1) return ans;
+        for (int ans = 0; q.size(); ++ans) {
+            for (int m = q.size(); m; --m) {
+                int cur = q.front();
                 q.pop();
+                if (cur == (1 << n) - 1) {
+                    return ans;
+                }
                 for (auto& s : stickers) {
-                    int nxt = state;
-                    vector<int> cnt(26);
-                    for (char& c : s) ++cnt[c - 'a'];
+                    int cnt[26]{};
+                    int nxt = cur;
+                    for (char& c : s) {
+                        ++cnt[c - 'a'];
+                    }
                     for (int i = 0; i < n; ++i) {
-                        int idx = target[i] - 'a';
-                        if (!(nxt & (1 << i)) && cnt[idx]) {
+                        int j = target[i] - 'a';
+                        if ((cur >> i & 1) == 0 && cnt[j] > 0) {
                             nxt |= 1 << i;
-                            --cnt[idx];
+                            --cnt[j];
                         }
                     }
                     if (!vis[nxt]) {
@@ -176,7 +183,6 @@ public:
                     }
                 }
             }
-            ++ans;
         }
         return -1;
     }
@@ -186,30 +192,28 @@ public:
 #### Go
 
 ```go
-func minStickers(stickers []string, target string) int {
-	q := []int{0}
+func minStickers(stickers []string, target string) (ans int) {
 	n := len(target)
+	q := []int{0}
 	vis := make([]bool, 1<<n)
 	vis[0] = true
-	ans := 0
-	for len(q) > 0 {
-		for t := len(q); t > 0; t-- {
-			state := q[0]
-			if state == (1<<n)-1 {
-				return ans
-			}
+	for ; len(q) > 0; ans++ {
+		for m := len(q); m > 0; m-- {
+			cur := q[0]
 			q = q[1:]
+			if cur == 1<<n-1 {
+				return
+			}
 			for _, s := range stickers {
-				nxt := state
-				cnt := make([]int, 26)
+				cnt := [26]int{}
 				for _, c := range s {
 					cnt[c-'a']++
 				}
+				nxt := cur
 				for i, c := range target {
-					idx := c - 'a'
-					if (nxt&(1<<i)) == 0 && cnt[idx] > 0 {
+					if cur>>i&1 == 0 && cnt[c-'a'] > 0 {
 						nxt |= 1 << i
-						cnt[idx]--
+						cnt[c-'a']--
 					}
 				}
 				if !vis[nxt] {
@@ -218,12 +222,50 @@ func minStickers(stickers []string, target string) int {
 				}
 			}
 		}
-		ans++
 	}
 	return -1
 }
 ```
 
+#### TypeScript
+
+```ts
+function minStickers(stickers: string[], target: string): number {
+    const n = target.length;
+    const q: number[] = [0];
+    const vis: boolean[] = Array(1 << n).fill(false);
+    vis[0] = true;
+    for (let ans = 0; q.length; ++ans) {
+        const qq: number[] = [];
+        for (const cur of q) {
+            if (cur === (1 << n) - 1) {
+                return ans;
+            }
+            for (const s of stickers) {
+                const cnt: number[] = Array(26).fill(0);
+                for (const c of s) {
+                    cnt[c.charCodeAt(0) - 97]++;
+                }
+                let nxt = cur;
+                for (let i = 0; i < n; ++i) {
+                    const j = target.charCodeAt(i) - 97;
+                    if (((cur >> i) & 1) === 0 && cnt[j]) {
+                        nxt |= 1 << i;
+                        cnt[j]--;
+                    }
+                }
+                if (!vis[nxt]) {
+                    vis[nxt] = true;
+                    qq.push(nxt);
+                }
+            }
+        }
+        q.splice(0, q.length, ...qq);
+    }
+    return -1;
+}
+```
+
 #### Rust
 
 ```rust