83 lines
2.1 KiB
C++
83 lines
2.1 KiB
C++
#include <bits/stdc++.h>
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using namespace std;
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using Coords = pair<int, int>;
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void moveTail(const Coords& head, Coords& tail){
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if(abs(head.first - tail.first) <= 1 && abs(head.second - tail.second) <= 1){
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return;
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}
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if(head.first == tail.first){
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if(head.second > tail.second){
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tail.second++;
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} else{
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tail.second--;
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}
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} else if(head.second == tail.second){
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if(head.first > tail.first){
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tail.first++;
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} else{
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tail.first--;
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}
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} else if(head.first > tail.first && head.second > tail.second){
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tail.first++;
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tail.second++;
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} else if(head.first < tail.first && head.second > tail.second){
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tail.first--;
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tail.second++;
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} else if(head.first > tail.first && head.second < tail.second){
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tail.first++;
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tail.second--;
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} else if(head.first < tail.first && head.second < tail.second){
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tail.first--;
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tail.second--;
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}
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}
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int main(){
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ifstream input_file("input.txt");
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string line;
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Coords head(0, 0), tail(0, 0);
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vector<Coords> body(8, {0,0});
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set<Coords> visited_by_tail;
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visited_by_tail.insert(tail);
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while(getline(input_file, line)){
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stringstream ss(line);
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char direction;
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int steps;
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ss >> direction >> steps;
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while(steps > 0){
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if(direction == 'R'){
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head.first++;
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} else if(direction == 'L'){
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head.first--;
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} else if(direction == 'U'){
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head.second++;
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} else if(direction == 'D'){
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head.second--;
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}
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moveTail(head, body[0]);
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for(size_t i = 0; i < body.size() - 1; ++i){
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moveTail(body[i], body[i+1]);
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}
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moveTail(body[7], tail);
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visited_by_tail.insert(tail);
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steps--;
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// cout << head.first << " " << head.second << " " << tail.first << " " << tail.second << '\n';
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}
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}
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cout << "Number of positions visited by the tail: " << visited_by_tail.size() << endl;
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return 0;
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} |