Weekly Contest 123

Author: MaskRay

add-to-array-form-of-integer.cc

@@ -0,0 +1,22 @@
+// Add to Array-Form of Integer
+#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:
+  vector<int> addToArrayForm(vector<int> &A, int K) {
+    reverse(ALL(A));
+    int n = A.size();
+    REP(i, n) {
+      if (!K) break;
+      int t = A[i] + K % 10;
+      K = K / 10 + t / 10;
+      A[i] = t % 10;
+    }
+    for (; K; K /= 10)
+      A.push_back(K % 10);
+    reverse(ALL(A));
+    return A;
+  }
+};

broken-calculator.cc

@@ -0,0 +1,10 @@
+// Broken Calculator
+class Solution {
+public:
+  int brokenCalc(int X, int Y) {
+    int r = 0;
+    for (; X < Y; r++)
+      Y = Y & 1 ? Y+1 : Y/2;
+    return r+X-Y;
+  }
+};

satisfiability-of-equality-equations.cc

@@ -0,0 +1,20 @@
+// Satisfiability of Equality Equations
+class Solution {
+public:
+  bool equationsPossible(vector<string> &equations) {
+    int p[26];
+    iota(p, p + 26, 0);
+    auto f = [&](int x) {
+      while (p[x] != x)
+        p[x] = p[p[x]], x = p[x];
+      return x;
+    };
+    for (auto &eq : equations)
+      if (eq[1] == '=')
+        p[f(eq[0]-'a')] = f(eq[3]-'a');
+    for (auto &eq : equations)
+      if (eq[1] == '!' && f(eq[0]-'a') == f(eq[3]-'a'))
+        return false;
+    return true;
+  }
+};

subarrays-with-k-different-integers.cc

@@ -0,0 +1,20 @@
+// Subarrays with K Different Integers
+#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 subarraysWithKDistinct(vector<int> &A, int K) {
+    int n = A.size(), j = 0, jj = 0, r = 0;
+    vector<int> c(n+1);
+    REP(i, n) {
+      while (j < n && K) c[A[j++]]++ || K--;
+      if (K) break;
+      jj = max(jj, j);
+      while (jj < n && c[A[jj]]) jj++;
+      r += jj-j+1;
+      --c[A[i]] || K++;
+    }
+    return r;
+  }
+};