Weekly Contest 115

Author: MaskRay

check-completeness-of-a-binary-tree.cc

@@ -0,0 +1,42 @@
+// Check Completeness of a Binary Tree
+class Solution {
+  int cc;
+  int c(TreeNode *x) {
+    return x ? 1 + c(x->left) + c(x->right) : 0;
+  }
+  bool f(TreeNode *x, int i) {
+    return !x || i < cc && f(x->left, 2*i+1) && f(x->right, 2*i+2);
+  }
+public:
+  bool isCompleteTree(TreeNode *root) {
+    cc = c(root);
+    return f(root, 0);
+  }
+};
+
+///
+
+class Solution {
+public:
+  bool isCompleteTree(TreeNode *root) {
+    vector<TreeNode *> cur{root}, suc;
+    for(;;) {
+      bool null = false;
+      for (auto *x : cur) {
+        if (!x->left) null = true;
+        else if (null) return false;
+        else suc.push_back(x->left);
+        if (!x->right) null = true;
+        else if (null) return false;
+        else suc.push_back(x->right);
+      }
+      cur.swap(suc);
+      suc.clear();
+      if (null) break;
+    }
+    for (auto *x: cur)
+      if (x->left || x->right)
+        return false;
+    return true;
+  }
+};

delete-columns-to-make-sorted-iii.cc

@@ -0,0 +1,23 @@
+// Delete Columns to Make Sorted III
+#define ALL(x) (x).begin(), (x).end()
+#define FOR(i, a, b) for (remove_cv<remove_reference<decltype(b)>::type>::type i = (a); i < (b); i++)
+#define REP(i, n) FOR(i, 0, n)
+
+class Solution {
+public:
+  int minDeletionSize(vector<string> &A) {
+    int m = A.size(), n = A[0].size();
+    vector<int> s(n);
+    REP(j, n) {
+      s[j] = 1;
+      REP(jj, j) {
+        char ok = 1;
+        REP(i, m)
+          ok &= A[i][jj] <= A[i][j];
+        if (ok)
+          s[j] = max(s[j], s[jj] + 1);
+      }
+    }
+    return n - *max_element(ALL(s));
+  }
+};

prison-cells-after-n-days.cc

@@ -0,0 +1,25 @@
+// Prison Cells After N Days
+#define FOR(i, a, b) for (remove_cv<remove_reference<decltype(b)>::type>::type i = (a); i < (b); i++)
+#define REP(i, n) FOR(i, 0, n)
+
+class Solution {
+public:
+  vector<int> prisonAfterNDays(vector<int> &cells, int N) {
+    int m = 8, x = 0;
+    vector<int> memo(1 << m, -1);
+    REP(i, m)
+      x |= cells[i] << i;
+    memo[x] = 0;
+    FOR(i, 1, N + 1) {
+      x = ~(x>>1^x<<1) & (1<<m-2)-1<<1;
+      if (memo[x] >= 0)
+        i = (N-memo[x])/(i-memo[x])*(i-memo[x])+memo[x];
+      else
+        memo[x] = i;
+    }
+    vector<int> r(m);
+    REP(i, m)
+      r[i] = x >> i & 1;
+    return r;
+  }
+};

regions-cut-by-slashes.cc

@@ -0,0 +1,32 @@
+// Regions Cut By Slashes
+#define ALL(x) (x).begin(), (x).end()
+#define FOR(i, a, b) for (remove_cv<remove_reference<decltype(b)>::type>::type i = (a); i < (b); i++)
+#define REP(i, n) FOR(i, 0, n)
+
+class Solution {
+public:
+  int regionsBySlashes(vector<string> &g) {
+    int n = g.size();
+    vector<int> uf(n*n*4);
+    iota(ALL(uf), 0);
+    auto f = [&](int x) {
+      while (uf[x] != x)
+        uf[x] = uf[uf[x]], x = uf[x];
+      return x;
+    };
+    auto me = [&](int x, int y) { uf[f(x)] = f(y); };
+    REP(i, n) REP(j, n) {
+      int t = (i*n+j)*4;
+      switch (g[i][j]) {
+      case '/': me(t+0, t+1); me(t+2, t+3); break;
+      case '\\': me(t+0, t+3); me(t+1, t+2); break;
+      default: me(t+0, t+1); me(t+1, t+2); me(t+2, t+3); break;
+      }
+      if (i) me(t+0, t-4*n+2);
+      if (j) me(t+1, t-4+3);
+    }
+    int r = 0;
+    REP(i, n*n*4) r += uf[i] == i;
+    return r;
+  }
+};