[#7] Add contest codes

Author: zeikar

ABC_181_A.cpp

@@ -0,0 +1,16 @@
+#include <iostream>
+#include <string>
+using namespace std;
+
+int main() {
+	int n;
+	cin >> n;
+	if (n%2==1)
+	{
+		cout << "Black" << endl;
+	}
+	else
+	{
+		cout << "White" << endl;
+	}
+}

ABC_181_B.cpp

@@ -0,0 +1,20 @@
+#include <iostream>
+#include <string>
+using namespace std;
+
+int main() {
+	long long n, a, b;
+	long long sum = 0;
+
+	cin >> n;
+
+	while (n--)
+	{
+		cin >> a >> b;
+
+		a--;
+		sum += (b * (b + 1) / 2) - (a * (a + 1) / 2);
+	}
+
+	cout << sum << endl;
+}

ABC_181_C.cpp

@@ -0,0 +1,55 @@
+#include <iostream>
+#include <algorithm>
+using namespace std;
+
+int x[100];
+int y[100];
+
+int main() {
+	int n;
+
+	cin >> n;
+
+	for (int i = 0; i < n; i++)
+	{
+		int a, b;
+
+		cin >> a >> b;
+
+		x[i] = a;
+		y[i] = b;
+	}
+
+	for (int i = 0; i < n; i++)
+	{
+		for (int j = 0; j < n; j++)
+		{
+			for (int k = 0; k < n; k++)
+			{
+				if (i == j || j == k || i == k)
+				{
+					continue;
+				}
+
+				if ((y[j] - y[i]) == 0 && (y[k] - y[j]) == 0)
+				{
+					cout << "Yes" << endl;
+					return 0;
+				}
+				else if ((y[j] - y[i]) == 0 || (y[k] - y[j]) == 0)
+				{
+					continue;
+				}
+
+
+				if ((double)((double)x[j] - x[i]) / ((double)y[j] - y[i]) == (double)((double)x[k] - x[j]) / ((double)y[k] - y[j]))
+				{
+					cout << "Yes" << endl;
+					return 0;
+				}
+			}
+		}
+	}
+
+	cout << "No" << endl;
+}

ABC_181_D.cpp

@@ -0,0 +1,65 @@
+#include <iostream>
+#include <string>
+#include <map>
+using namespace std;
+
+int digits[10];
+
+bool isAvailable(int n) {
+	int temp[10];
+	for (int i = 0; i < 10; i++)
+	{
+		temp[i] = digits[i];
+	}
+
+	int num = n;
+	while (num != 0)
+	{
+		int d = num % 10;
+
+		if (temp[d] > 0)
+		{
+			temp[d]--;
+		}
+		else
+		{
+			return false;
+		}
+
+		num /= 10;
+	}
+
+	if (n < 100)
+	{
+		for (int i = 0; i < 10; i++)
+		{
+			if (temp[i] != 0)
+			{
+				return false;
+			}
+		}
+	}
+
+	return true;
+}
+
+int main() {
+	string s;
+	cin >> s;
+
+	for (int i = 0; i < s.length(); i++)
+	{
+		digits[s[i] - '0']++;
+	}
+
+	int num = 0;
+	for (int i = 8; i < 1000; i += 8)
+	{
+		if (isAvailable(i))
+		{
+			cout << "Yes" << endl;
+			return 0;
+		}
+	}
+	cout << "No" << endl;
+}

ABC_184_A.cpp

@@ -0,0 +1,8 @@
+#include <iostream>
+using namespace std;
+
+int main() {
+	int a, b, c, d;
+	cin >> a >> b >> c >> d;
+	cout << a * d - b * c << endl;
+}

ABC_184_B.cpp

@@ -0,0 +1,24 @@
+#include <iostream>
+#include <string>
+using namespace std;
+
+int main() {
+	int n, x;
+	string str;
+
+	cin >> n >> x >> str;
+
+	for (int i = 0; i < str.size(); i++)
+	{
+		if (str[i] == 'o')
+		{
+			x++;
+		}
+		else if (x > 0)
+		{
+			x--;
+		}
+	}
+
+	cout << x << endl;
+}

ABC_184_E.cpp

@@ -0,0 +1,98 @@
+#include <iostream>
+#include <queue>
+#include <utility>
+#include <string>
+#include <cstring>
+using namespace std;
+
+string maps[2000];
+int visited[2000][2000];
+bool teleported[26];
+
+vector<pair<int, int> > teleport[26];
+pair<int, int> start, goal;
+
+int dir[][2] = { -1, 0, 0, -1, 0, 1,1,0 };
+
+int main() {
+	int h, w;
+
+	cin >> h >> w;
+
+	for (int i = 0; i < h; i++)
+	{
+		cin >> maps[i];
+
+		for (int j = 0; j < maps[i].size(); j++)
+		{
+			if (maps[i][j] >= 'a' && maps[i][j] <= 'z')
+			{
+				teleport[maps[i][j] - 'a'].push_back(make_pair(i, j));
+			}
+			else if (maps[i][j] == 'S')
+			{
+				start = make_pair(i, j);
+			}
+			else if (maps[i][j] == 'G')
+			{
+				goal = make_pair(i, j);
+			}
+		}
+	}
+
+	memset(visited, -1, sizeof(visited));
+
+	int result = -1;
+
+	queue< pair<int, int> > que;
+	que.push(start);
+	visited[start.first][start.second] = 0;
+
+	while (!que.empty())
+	{
+		pair<int, int> next = que.front();
+		que.pop();
+
+		if (next.first == goal.first && next.second == goal.second)
+		{
+			result = visited[next.first][next.second];
+			break;
+		}
+
+		for (int d = 0; d < 4; d++)
+		{
+			int x = next.first + dir[d][0];
+			int y = next.second + dir[d][1];
+
+			if (x >= h || x < 0 || y >= w || y < 0 || visited[x][y] != -1 || maps[x][y] == '#')
+			{
+				continue;
+			}
+
+			visited[x][y] = visited[next.first][next.second] + 1;
+			que.push(make_pair(x, y));
+		}
+
+		// teleport
+		if (maps[next.first][next.second] >= 'a' && maps[next.first][next.second] <= 'z' && teleported[maps[next.first][next.second] - 'a'] == false)
+		{
+			teleported[maps[next.first][next.second] - 'a'] = true;
+
+			for (int i = 0; i < teleport[maps[next.first][next.second] - 'a'].size(); i++)
+			{
+				int x = teleport[maps[next.first][next.second] - 'a'][i].first;
+				int y = teleport[maps[next.first][next.second] - 'a'][i].second;
+
+				if (x >= h || x < 0 || y >= w || y < 0 || visited[x][y] != -1 || maps[x][y] == '#')
+				{
+					continue;
+				}
+
+				visited[x][y] = visited[next.first][next.second] + 1;
+				que.push(make_pair(x, y));
+			}
+		}
+	}
+
+	cout << result << endl;
+}

ABC_184_F.cpp

@@ -0,0 +1,79 @@
+// https://www.geeksforgeeks.org/meet-in-the-middle/
+
+// C++ program to demonstrate working of Meet in the 
+// Middle algorithm for maximum subset sum problem. 
+#include <iostream>
+#include <algorithm>
+using namespace std;
+typedef long long int ll;
+ll X[1 << 21], Y[1 << 21];
+
+// Find all possible sum of elements of a[] and store 
+// in x[] 
+void calcsubarray(ll a[], ll x[], int n, int c)
+{
+	for (int i = 0; i < (1 << n); i++)
+	{
+		ll s = 0;
+		for (int j = 0; j < n; j++)
+			if (i & (1 << j))
+				s += a[j + c];
+		x[i] = s;
+	}
+}
+
+// Returns the maximum possible sum less or equal to S 
+ll solveSubsetSum(ll a[], int n, ll S)
+{
+	// Compute all subset sums of first and second 
+	// halves 
+	calcsubarray(a, X, n / 2, 0);
+	calcsubarray(a, Y, n - n / 2, n / 2);
+
+	int size_X = 1 << (n / 2);
+	int size_Y = 1 << (n - n / 2);
+
+	// Sort Y (we need to do doing binary search in it) 
+	sort(Y, Y + size_Y);
+
+	// To keep track of the maximum sum of a subset 
+	// such that the maximum sum is less than S 
+	ll max = 0;
+
+	// Traverse all elements of X and do Binary Search 
+	// for a pair in Y with maximum sum less than S. 
+	for (int i = 0; i < size_X; i++)
+	{
+		if (X[i] <= S)
+		{
+			// lower_bound() returns the first address 
+			// which has value greater than or equal to 
+			// S-X[i]. 
+			int p = lower_bound(Y, Y + size_Y, S - X[i]) - Y;
+
+			// If S-X[i] was not in array Y then decrease 
+			// p by 1 
+			if (p == size_Y || Y[p] != (S - X[i]))
+				p--;
+
+			if ((Y[p] + X[i]) > max)
+				max = Y[p] + X[i];
+		}
+	}
+	return max;
+}
+
+// Driver code 
+int main()
+{
+	int n, t;
+	ll a[40];
+
+	cin >> n >> t;
+	for (int i = 0; i < n; i++)
+	{
+		cin >> a[i];
+	}
+
+	cout << solveSubsetSum(a, n, t) << endl;
+}

ABC_187_A.cpp

@@ -0,0 +1,12 @@
+#include <iostream>
+#include <string>
+#include <algorithm>
+using namespace std;
+
+int main() {
+	string a, b;
+
+	cin >> a >> b;
+
+	cout << max((a[0] + a[1] + a[2] - '0' * 3), b[0] + b[1] + b[2] - '0' * 3) << endl;
+}