finish day 2

02/example

@@ -0,0 +1,6 @@
+7 6 4 2 1
+1 2 7 8 9
+9 7 6 2 1
+1 3 2 4 5
+8 6 4 4 1
+1 3 6 7 9

02/main.cc

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+#include <fstream>
+#include <iostream>
+#include <sstream>
+#include <string>
+#include <vector>
+using namespace std;
+
+bool checkSequence(vector<int> nums) {
+  // signals whether we are checking for greater or lower numbers
+  // -1 - lower
+  //  0 - no order yet
+  //  1 - greater 
+  int greater = 0;
+  int drag = nums[0];
+
+  for (int i = 1; i < nums.size(); i++) {
+    // check difference first
+    if (drag == nums[i] || drag - nums[i] > 3 || drag - nums[i] < -3) {
+      return false;
+    }
+
+    // check order
+    if (greater == 0) {
+      if (drag < nums[i]) greater = 1;
+      else if (drag > nums[i]) greater = -1;
+    }
+    else if (greater > 0) {
+      if (drag >= nums[i]) return false;
+    }
+    else if (greater < 0) {
+      if (drag <= nums[i]) return false;
+    }
+
+    drag = nums[i];
+  }
+  return true;
+}
+
+void lineToVector(string line, vector<int> &nums) {
+  // stream for convenience
+  stringstream line_stream;
+  line_stream << line;
+
+  int a;
+
+  while (line_stream >> a) {
+    nums.push_back(a);
+  }
+}
+
+bool checkSequenceDampened(vector<int> nums) {
+  if (checkSequence(nums)) return true;
+
+  for (int i = 0; i < nums.size(); i++) {
+    int temp = nums[i];
+
+    nums.erase(nums.begin() + i);
+    if (checkSequence(nums)) return true;
+    nums.insert(nums.begin() + i , temp);
+  }
+
+  return false;
+}
+
+int main(int argc, char *argv[]) {
+  ifstream input_stream("input");
+  string line;
+  int sum = 0;
+  int dampened_sum = 0;
+
+  while (getline(input_stream, line)) {
+    // convert line to int sequence
+    vector<int> nums;
+    lineToVector(line, nums);
+
+    if (checkSequence(nums)) sum++;
+    if (checkSequenceDampened(nums)) dampened_sum++;
+  }
+
+  cout << "number of safe lines is: " << sum << endl;
+  cout << "number of safe lines (dampened) is: " << dampened_sum << endl;
+  return 0;
+}