feat: leetcode contest 292

Author: upupming

leetcode/contest-292/6056. Largest 3-Same-Digit Number in String.js

@@ -0,0 +1,15 @@
+/**
+ * @param {string} num
+ * @return {string}
+ */
+const largestGoodInteger = function (num) {
+  let ans = ''; let m = -1
+  for (let i = 0; i <= num.length - 3; i++) {
+    const x = num.charCodeAt(i) - '0'.charCodeAt(0)
+    if (x > m && num[i] === num[i + 1] && num[i] === num[i + 2]) {
+      ans = num.slice(i, i + 3)
+      m = x
+    }
+  }
+  return ans
+}

leetcode/contest-292/6057. Count Nodes Equal to Average of Subtree.js

@@ -0,0 +1,25 @@
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val, left, right) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.left = (left===undefined ? null : left)
+ *     this.right = (right===undefined ? null : right)
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @return {number}
+ */
+ var averageOfSubtree = function(root) {
+  let ans = 0
+  const dfs = (node) => {
+      if (!node) return [0, 0]
+      let [l, lCnt] = dfs(node.left)
+      let [r, rCnt] = dfs(node.right)
+      let sum = (l+r+node.val), cnt = lCnt+rCnt+1
+      if (Math.floor(sum / cnt) === node.val) ans++
+      return [sum, cnt]
+  }
+  dfs(root)
+  return ans
+};

leetcode/contest-292/6058. Count Number of Texts.js

@@ -0,0 +1,26 @@
+const P = 1e9 + 7
+const dp3 = [1]; const dp4 = [1]
+for (let i = 1; i < 1e5 + 10; i++) {
+  dp3[i] = ((dp3[i - 1] ?? 0) + (dp3[i - 2] ?? 0) + (dp3[i - 3] ?? 0)) % P
+  dp4[i] = ((dp4[i - 1] ?? 0) + (dp4[i - 2] ?? 0) + (dp4[i - 3] ?? 0) + (dp4[i - 4] ?? 0)) % P
+}
+
+/**
+ * @param {string} pressedKeys
+ * @return {number}
+ */
+const countTexts = function (pk) {
+  const n = pk.length
+  let ans = 1
+  for (let i = 0; i < n;) {
+    let j = i; const ch = pk[i]
+    while (j < n && pk[j] === ch) {
+      j++
+    }
+    // console.log(i, j, j-i, dp[j-i])
+    const dp = '79'.includes(ch) ? dp4 : dp3
+    ans = Number((BigInt(ans) * BigInt(dp[j - i])) % BigInt(P))
+    i = j
+  }
+  return ans
+}

leetcode/contest-292/6059. Check if There Is a Valid Parentheses String Path.js

@@ -0,0 +1,31 @@
+/**
+ * @param {character[][]} grid
+ * @return {boolean}
+ */
+const hasValidPath = function (grid) {
+  const m = grid.length; const n = grid[0].length
+  grid = grid.map(g => g.map((a) => a === '(' ? 1 : -1))
+  if ((m + n) % 2 === 0) return false
+  const max = Array(m).fill(0).map(() => Array(n).fill(-1e5))
+  const min = Array(m).fill(0).map(() => Array(n).fill(1e5))
+  if (grid[0][0] >= 0) min[0][0] = grid[0][0], max[0][0] = grid[0][0]
+  // console.log(grid)
+  for (let i = 0; i < m; i++) {
+    for (let j = 0; j < n; j++) {
+      // 从 [i-1, j] 过来
+      if (i >= 1) {
+        // tmpMin < 0 但是 tmpMax >= 0 的情况，我们 i, j 仍然合法，min 值为 0
+        const tmpMin = min[i - 1][j] + grid[i][j]; const tmpMax = max[i - 1][j] + grid[i][j]
+        if (tmpMax >= 0) min[i][j] = Math.min(min[i][j], Math.max(tmpMin, 0))
+        if (tmpMax >= 0) max[i][j] = Math.max(max[i][j], tmpMax)
+      }
+      // 从 [i, j-1] 过来
+      if (j >= 1) {
+        const tmpMin = min[i][j - 1] + grid[i][j]; const tmpMax = max[i][j - 1] + grid[i][j]
+        if (tmpMax >= 0) min[i][j] = Math.min(min[i][j], Math.max(tmpMin, 0))
+        if (tmpMax >= 0) max[i][j] = Math.max(max[i][j], tmpMax)
+      }
+    }
+  }
+  return min[m - 1][n - 1] === 0 && max[m - 1][n - 1] >= 0
+}