217/239

Author: MaskRay

README.md

@@ -2,7 +2,7 @@
 
 [LeetCode solutions](http://maskray.me/blog/2014-06-29-leetcode-solutions) gives some thoughts on selected problems.
 
-Solved 211/220 problems.
+Solved 217/239 problems.
 
 ## Database
 
@@ -12,6 +12,25 @@ See [database.md](database.md)
 
 | # | Title | Solution |
 |---| ----- | -------- |
+|255|[Verify Preorder Sequence in Binary Search Tree](/problems/verify-preorder-sequence-in-binary-search-tree/)|[verify-preorder-sequence-in-binary-search-tree.cc](verify-preorder-sequence-in-binary-search-tree.cc)|
+|254|[Factor Combinations](/problems/factor-combinations/)|[factor-combinations.cc](factor-combinations.cc)|
+|253|[Meeting Rooms II](/problems/meeting-rooms-ii/)|[meeting-rooms-ii.cc](meeting-rooms-ii.cc)|
+|252|[Meeting Rooms](/problems/meeting-rooms/)|[meeting-rooms.cc](meeting-rooms.cc)|
+|251|[Flatten 2D Vector](/problems/flatten-2d-vector/)|[flatten-2d-vector.cc](flatten-2d-vector.cc)|
+|250|[Count Univalue Subtrees](/problems/count-univalue-subtrees/)|[count-univalue-subtrees.cc](count-univalue-subtrees.cc)|
+|249|[Group Shifted Strings](/problems/group-shifted-strings/)|[group-shifted-strings.cc](group-shifted-strings.cc)|
+|248|[Strobogrammatic Number III](/problems/strobogrammatic-number-iii/)|[strobogrammatic-number-iii.cc](strobogrammatic-number-iii.cc)|
+|247|[Strobogrammatic Number II](/problems/strobogrammatic-number-ii/)|[strobogrammatic-number-ii.cc](strobogrammatic-number-ii.cc)|
+|246|[Strobogrammatic Number](/problems/strobogrammatic-number/)|[strobogrammatic-number.cc](strobogrammatic-number.cc)|
+|245|[Shortest Word Distance III](/problems/shortest-word-distance-iii/)|[shortest-word-distance-iii.cc](shortest-word-distance-iii.cc)|
+|244|[Shortest Word Distance II](/problems/shortest-word-distance-ii/)|[shortest-word-distance-ii.cc](shortest-word-distance-ii.cc)|
+|243|[Shortest Word Distance](/problems/shortest-word-distance/)|[shortest-word-distance.cc](shortest-word-distance.cc)|
+|242|[Valid Anagram](/problems/valid-anagram/)|[valid-anagram.cc](valid-anagram.cc)|
+|241|[Different Ways to Add Parentheses](/problems/different-ways-to-add-parentheses/)|[different-ways-to-add-parentheses.cc](different-ways-to-add-parentheses.cc)|
+|240|[Search a 2D Matrix II](/problems/search-a-2d-matrix-ii/)|[search-a-2d-matrix-ii.cc](search-a-2d-matrix-ii.cc)|
+|239|[Sliding Window Maximum](/problems/sliding-window-maximum/)|[sliding-window-maximum.cc](sliding-window-maximum.cc)|
+|238|[Product of Array Except Self](/problems/product-of-array-except-self/)|[product-of-array-except-self.cc](product-of-array-except-self.cc)|
+|237|[Delete Node in a Linked List](/problems/delete-node-in-a-linked-list/)|[delete-node-in-a-linked-list.cc](delete-node-in-a-linked-list.cc)|
 |236|[Lowest Common Ancestor of a Binary Tree](/problems/lowest-common-ancestor-of-a-binary-tree/)|[lowest-common-ancestor-of-a-binary-tree.cc](lowest-common-ancestor-of-a-binary-tree.cc)|
 |235|[Lowest Common Ancestor of a Binary Search Tree](/problems/lowest-common-ancestor-of-a-binary-search-tree/)|[lowest-common-ancestor-of-a-binary-search-tree.cc](lowest-common-ancestor-of-a-binary-search-tree.cc)|
 |234|[Palindrome Linked List](/problems/palindrome-linked-list/)|[palindrome-linked-list.cc](palindrome-linked-list.cc)|
@@ -183,7 +202,7 @@ See [database.md](database.md)
 |52|[N-Queens II](/problems/n-queens-ii/)|[n-queens-ii.cc](n-queens-ii.cc)|
 |51|[N-Queens](/problems/n-queens/)|[n-queens.cc](n-queens.cc)|
 |50|[Pow(x, n)](/problems/powx-n/)|[powx-n.cc](powx-n.cc)|
-|49|[Anagrams](/problems/anagrams/)|[anagrams.cc](anagrams.cc)|
+|49|[Group Anagrams](/problems/anagrams/)|[anagrams.cc](anagrams.cc)|
 |48|[Rotate Image](/problems/rotate-image/)|[rotate-image.cc](rotate-image.cc)|
 |47|[Permutations II](/problems/permutations-ii/)|[permutations-ii.cc](permutations-ii.cc)|
 |46|[Permutations](/problems/permutations/)|[permutations.cc](permutations.cc)|

delete-node-in-a-linked-list.cc

@@ -0,0 +1,22 @@
+// Delete Node in a Linked List
+class Solution {
+public:
+  void deleteNode(ListNode *x) {
+    auto y = x->next;
+    swap(x->val, y->val);
+    x->next = y->next;
+    delete y;
+  }
+};
+
+//
+
+class Solution {
+public:
+  void deleteNode(ListNode* x) {
+    ListNode *y;
+    for (; x->next; y = x, x = x->next)
+      x->val = x->next->val;
+    y->next = 0;
+  }
+};

different-ways-to-add-parentheses.cc

@@ -0,0 +1,38 @@
+// Different Ways to Add Parentheses
+#define REP(i, n) FOR(i, 0, n)
+#define FOR(i, a, b) for (int i = (a); i < (b); i++)
+#define ROF(i, a, b) for (int i = (b); --i >= (a); )
+
+class Solution {
+public:
+  vector<int> diffWaysToCompute(string input) {
+    vector<int> nums;
+    vector<char> ops;
+    for (int j = 0, i = 0; i < input.size(); i = j) {
+      int x = 0;
+      for (; j < input.size() && isdigit(input[j]); j++)
+        x = x*10+input[j]-'0';
+      nums.push_back(x);
+      if (j < input.size())
+        ops.push_back(input[j++]);
+    }
+    int n = nums.size();
+    vector<vector<vector<int>>> s(n, vector<vector<int>>(n));
+    REP(i, n)
+      s[i][i].push_back(nums[i]);
+    ROF(i, 0, n)
+      FOR(j, i+1, n)
+        FOR(k, i, j)
+          for (auto x: s[i][k])
+            for (auto y: s[k+1][j])
+              s[i][j].push_back(op(ops[k], x, y));
+    return s[0][n-1];
+  }
+  int op(char c, int x, int y) {
+    switch (c) {
+    case '+': return x+y;
+    case '-': return x-y;
+    default: return x*y;
+    }
+  }
+};

product-of-array-except-self.cc

@@ -0,0 +1,22 @@
+// Product of Array Except Self
+#define FOR(i, a, b) for (int i = (a); i < (b); i++)
+#define REP(i, n) FOR(i, 0, n)
+#define ROF(i, a, b) for (int i = (b); --i >= (a); )
+
+class Solution {
+public:
+  vector<int> productExceptSelf(vector<int> &a) {
+    int n = (int)a.size(), s = 1;
+    vector<int> b(n);
+    REP(i, n) {
+      b[i] = s;
+      s *= a[i];
+    }
+    s = 1;
+    ROF(i, 0, n) {
+      b[i] *= s;
+      s *= a[i];
+    }
+    return b;
+  }
+};

search-a-2d-matrix-ii.cc

@@ -0,0 +1,30 @@
+// Search a 2D Matrix II
+class Solution {
+public:
+  bool searchMatrix(vector<vector<int>> &a, int x) {
+    if (a.empty() || a[0].empty()) return false;
+    return f(a, 0, a.size(), 0, a[0].size(), x);
+  }
+  bool f(vector<vector<int>> &a, int u, int uu, int v, int vv, int x) {
+    if (u >= uu || v >= vv) return false;
+    if (uu-u > vv-v) {
+      int q = (v+vv)/2, l = u, h = uu;
+      while (l < h) {
+        int m = (l+h)/2;
+        if (a[m][q] < x) l = m+1;
+        else h = m;
+      }
+      if (l < uu && a[l][q] == x) return true;
+      return f(a, u, l, q+1, vv, x) || f(a, l, uu, v, q, x);
+    } else {
+      int p = (u+uu)/2, l = v, h = vv;
+      while (l < h) {
+        int m = (l+h)/2;
+        if (a[p][m] < x) l = m+1;
+        else h = m;
+      }
+      if (l < vv && a[p][l] == x) return true;
+      return f(a, p+1, uu, v, l, x) || f(a, u, p, l, vv, x);
+    }
+  }
+};

sliding-window-maximum.cc

@@ -0,0 +1,22 @@
+// Sliding Window Maximum
+#define FOR(i, a, b) for (int i = (a); i < (b); i++)
+#define REP(i, n) FOR(i, 0, n)
+
+class Solution {
+public:
+  vector<int> maxSlidingWindow(vector<int> &a, int k) {
+    int n = (int)a.size();
+    vector<int> b;
+    deque<int> q;
+    REP(i, n) {
+      if (q.size() && q.front() <= i-k)
+        q.pop_front();
+      while (q.size() && a[q.back()] < a[i])
+        q.pop_back();
+      q.push_back(i);
+      if (i >= k-1)
+        b.push_back(a[q.front()]);
+    }
+    return b;
+  }
+};

valid-anagram.cc

@@ -0,0 +1,15 @@
+// Valid Anagram
+class Solution {
+public:
+  bool isAnagram(string s, string t) {
+    int c[26] = {};
+    for (auto a: s)
+      c[a-'a']++;
+    for (auto a: t)
+      c[a-'a']--;
+    for (auto a: c)
+      if (a)
+        return false;
+    return true;
+  }
+};