csacademy round#50

checksquare.cpp

// can try http://mathworld.wolfram.com/ConvexHull.html, but overkill..
#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;

int Dist(pair<int, int> a, pair<int, int> b) {
	return (a.first - b.first) * (a.first - b.first) +
		(a.second - b.second) * (a.second - b.second);
}

int main() {
	vector<pair<int, int>> coords(4);
	int t;
	cin >> t;
	while (t--) {
		int mn_y = 1005, mx_y = -1, mn_x = 1005, mx_x = -1;
		for (int i = 0; i < 4; i += 1) {
			cin >> coords[i].first >> coords[i].second;

			mn_x = min(mn_x, coords[i].first);
			mx_x = max(mx_x, coords[i].first);
			mn_y = min(mn_y, coords[i].second);
			mx_y = max(mx_y, coords[i].second);
		}

    // mathmatical theory in square: https://en.wikipedia.org/wiki/File:01-Quadrat-Diagonale-gegeben.gif
		if (mx_x - mn_x != mx_y - mn_y) {
			cout << 0 << "\n";
			continue;
		}

		vector<int> order = { 0, 1, 2, 3 };

		bool k = false;
		do {
			int dist = Dist(coords[order[0]], coords[order[1]]);
			bool ok = true;
			for (int i = 0; i < 4; i += 1) {
				if (dist != Dist(coords[order[i]], coords[order[(i + 1) % 4]])) {
					ok = false;
				}
			}

			if (ok) {
				cout << 1 << '\n';
				k = true;
				break;
			}
		} while (next_permutation(order.begin(), order.end())); // http://en.cppreference.com/w/cpp/algorithm/next_permutation

		if (not k) {
			cout << 0 << '\n';
		}
	}
	return 0;
}

friday13.cpp

#include <bits/stdc++.h>
using namespace std;

vector<string> weekDays{"Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday"};
vector<int> days{31,28,31,30,31,30,31,31,30,31,30,31};

int main() {
    string startDay;
    cin >> startDay;
    int day = find(weekDays.begin(), weekDays.end(), startDay) - weekDays.begin(); // vector iterator operation (+, -)
    
    int res = 0;
    for (int month = 0; month < 12; ++month) {
        for (int i = 0; i < days[month]; ++i) {
            if (i == 12 && day == 4) {
                ++res;
            }
            day = (day + 1) % 7;  // convenient zero-based index
        }
    }
    cout << res << "\n";
}

minrace.cpp

#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

int patienceSorting(int n, vector<int> els) {
	vector<int> piles; // save greatest value of each pile

	for (auto itr : els) {
		if (piles.size()) {
			vector<int>::iterator low = lower_bound(piles.begin(), piles.end(), itr-1, [](int a, int b) { return a > b; });
			int pos = low - piles.begin();
			if (low != end(piles)) {
				if (*low < itr) {
					*low = itr;
					continue;
				}
			}
		}
		piles.push_back(itr);
	}

	return piles.size();
}

int main() {
	int n, k; cin >> n >> k;
	vector<int> els(n);
	for (int i = 0; i < n; i += 1) {
		int group, racer; cin >> group >> racer;
		els[racer - 1] = group;
	}

	cout << patienceSorting(n, els) << '\n';
	return 0;
}

travel-distance.cpp

#include <bits/stdc++.h> // http://www.geeksforgeeks.org/bitsstdc-h-c/
using namespace std;

const int MAX_LEN = 1000;

int main() {
    string s;
    cin >> s;
    assert(1 <= s.size() && s.size() <= MAX_LEN);
    
    int x = 0, y = 0;
    for (auto it : s) { // https://solarianprogrammer.com/2014/08/21/cpp-14-auto-tutorial/
        if (it == 'N') {
            x += 1;
        } else if (it == 'E') {
            y += 1;
        } else if (it == 'S') {
            x -= 1;
        } else if (it == 'W') {
            y -= 1;
        } else {
            return 1;
        }
    }
    cout << abs(x) + abs(y) << "\n";
}