⚡ 1178

Author: Gan Kai

1178.猜字谜.js

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+/*
+ * @lc app=leetcode.cn id=1178 lang=javascript
+ *
+ * [1178] 猜字谜
+ */
+
+// @lc code=start
+/**
+ * @param {string[]} words
+ * @param {string[]} puzzles
+ * @return {number[]}
+ */
+var findNumOfValidWords = function(words, puzzles) {
+  const frequency = new Map();
+
+  for (const word of words) {
+      let mask = 0;
+      for (const ch of word) {
+          mask |= (1 << (ch.charCodeAt() - 'a'.charCodeAt()));
+      }
+      if (CountOne(mask) <= 7) {
+          frequency.set(mask, (frequency.get(mask) || 0) + 1);
+      }
+  }
+
+  const ans = [];
+  for (const puzzle of puzzles) {
+      let total = 0;
+
+      // 枚举子集方法一
+      // for (let choose = 0; choose < (1 << 6); ++choose) {
+      //     let mask = 0;
+      //     for (let i = 0; i < 6; ++i) {
+      //         if (choose & (1 << i)) {
+      //             mask |= (1 << (puzzle[i + 1].charCodeAt() - 'a'.charCodeAt()));
+      //         }
+      //     }
+      //     mask |= (1 << (puzzle[0].charCodeAt() - 'a'.charCodeAt()));
+      //     if (frequency.has(mask)) {
+      //         total += frequency.get(mask);
+      //     }
+      // }
+      // 枚举子集方法二
+      let mask = 0;
+      for (let i = 1; i < 7; ++i) {
+          mask |= (1 << (puzzle[i].charCodeAt() - 'a'.charCodeAt()));
+      }
+      let subset = mask;
+      while (subset) {
+          let s = subset | (1 << (puzzle[0].charCodeAt() - 'a'.charCodeAt()));
+          if (frequency.has(s)) {
+              total += frequency.get(s);
+          }
+          subset = (subset - 1) & mask;
+      }
+      // 在枚举子集的过程中，要么会漏掉全集 mask，要么会漏掉空集
+      // 这里会漏掉空集，因此需要额外判断空集
+      if (frequency.has(1 << (puzzle[0].charCodeAt() - 'a'.charCodeAt()))) {
+          total += frequency.get(1 << (puzzle[0].charCodeAt() - 'a'.charCodeAt()));
+      }
+      ans.push(total);
+  }
+  return ans;
+};
+
+function CountOne(n) {
+  const str = n.toString(2);
+  let count = 0;
+  for (const ch of str) {
+      if (parseInt(ch) === 1) {
+          count++;
+      }
+  }
+  return count;
+}
+// @lc code=end
+