add khushal87 codes

Binary Search/number_of_smaller_or_equal_elements_than_target.cpp

@@ -0,0 +1,23 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+int binarySearch(vector<int> arr, int n, int el)
+{
+ int start = 0;
+ int end = n - 1;
+ int res = 0;
+ while (start <= end)
+ {
+ int mid = start + (end - start) / 2;
+ if (arr[mid] <= el)
+ {
+ res = mid + 1;
+ start = mid + 1;
+ }
+ else if (arr[mid] > el)
+ {
+ end = mid - 1;
+ }
+ }
+ return res;
+}

Binary Search/single_element_in_sorted_array.cpp

@@ -0,0 +1,39 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+int solve(vector<int> &nums)
+{
+ int n = nums.size();
+ int start = 0;
+ int end = n - 1;
+
+ while (start <= end)
+ {
+ int mid = start + (end - start) / 2;
+ if (mid > 0 && mid < n - 1)
+ {
+ if (nums[mid] != nums[mid + 1] || nums[mid] != nums[mid - 1])
+ {
+ return nums[mid];
+ }
+ else if (nums[mid] == nums[mid - 1])
+ {
+ end = mid - 1;
+ }
+ else if (nums[mid] == nums[mid + 1])
+ {
+ start = mid + 1;
+ }
+ }
+ else if (mid == 0)
+ {
+ if (nums[mid] != nums[mid + 1])
+ return mid;
+ }
+ else if (mid == n - 1)
+ {
+ if (nums[mid] != nums[mid - 1])
+ return mid;
+ }
+ }
+}

Dynamic Programming/count_of_subset_sum_of_given_sum.cpp

@@ -0,0 +1,47 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+int solve(int p[], int n, int cap)
+{
+ int t[n + 1][cap + 1];
+ for (int i = 0; i <= n; i++)
+ {
+ for (int j = 0; j <= cap; j++)
+ {
+ if (j == 0)
+ {
+ t[i][j] = 1;
+ }
+ else if (i == 0 && j > 0)
+ {
+ t[i][j] = 0;
+ }
+ else
+ {
+ if (p[i - 1] <= j)
+ {
+ t[i][j] = t[i - 1][j - p[i - 1]] + t[i - 1][j];
+ }
+ else
+ {
+ t[i][j] = t[i - 1][j];
+ }
+ }
+ }
+ }
+ return t[n][cap];
+}
+
+int main()
+{
+ int n;
+ cin >> n;
+ int p[n];
+ for (int i = 0; i < n; i++)
+ {
+ cin >> p[i];
+ }
+ int cap;
+ cin >> cap;
+ cout << solve(p, n, cap) << endl;
+}

Dynamic Programming/equal_sum_partition.cpp

@@ -0,0 +1,57 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+#include <bits/stdc++.h>
+using namespace std;
+
+bool solve(int p[], int n, int cap)
+{
+ bool t[n + 1][cap + 1];
+ for (int i = 0; i <= n; i++)
+ {
+ for (int j = 0; j <= cap; j++)
+ {
+ if (j == 0)
+ {
+ t[i][j] = true;
+ }
+ else if (i == 0 && j > 0)
+ {
+ t[i][j] = false;
+ }
+ else
+ {
+ if (p[i - 1] <= j)
+ {
+ t[i][j] = t[i - 1][j - p[i - 1]] || t[i - 1][j];
+ }
+ else
+ {
+ t[i][j] = t[i - 1][j];
+ }
+ }
+ }
+ }
+ return t[n][cap];
+}
+
+int main()
+{
+ int n;
+ cin >> n;
+ int p[n];
+ int sum = 0;
+ for (int i = 0; i < n; i++)
+ {
+ cin >> p[i];
+ sum += p[i];
+ }
+ if (sum & 1)
+ {
+ cout << "Not possible" << endl;
+ }
+ else
+ {
+ cout << solve(p, n, sum / 2) << endl;
+ }
+}

Dynamic Programming/knapsack.cpp

@@ -0,0 +1,40 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+int solve(int p[], int w[], int n, int cap)
+{
+ int t[n + 1][cap + 1];
+ for (int i = 0; i <= n; i++)
+ {
+ for (int j = 0; j <= cap; j++)
+ {
+ if (i == 0 || j == 0)
+ {
+ t[i][j] = 0;
+ }
+ else if (w[i - 1] <= j)
+ {
+ t[i][j] = max(p[i - 1] + t[i - 1][j - w[i - 1]], t[i - 1][j]);
+ }
+ else
+ {
+ t[i][j] = t[i - 1][j];
+ }
+ }
+ }
+ return t[n][cap];
+}
+
+int main()
+{
+ int n;
+ cin >> n;
+ int p[n], w[n];
+ for (int i = 0; i < n; i++)
+ {
+ cin >> p[i] >> w[i];
+ }
+ int cap;
+ cin >> cap;
+ cout << solve(p, w, n, cap) << endl;
+}

Dynamic Programming/subset_sum.cpp

@@ -0,0 +1,47 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+bool solve(int p[], int n, int cap)
+{
+ bool t[n + 1][cap + 1];
+ for (int i = 0; i <= n; i++)
+ {
+ for (int j = 0; j <= cap; j++)
+ {
+ if (j == 0)
+ {
+ t[i][j] = true;
+ }
+ else if (i == 0 && j > 0)
+ {
+ t[i][j] = false;
+ }
+ else
+ {
+ if (p[i - 1] <= j)
+ {
+ t[i][j] = t[i - 1][j - p[i - 1]] || t[i - 1][j];
+ }
+ else
+ {
+ t[i][j] = t[i - 1][j];
+ }
+ }
+ }
+ }
+ return t[n][cap];
+}
+
+int main()
+{
+ int n;
+ cin >> n;
+ int p[n];
+ for (int i = 0; i < n; i++)
+ {
+ cin >> p[i];
+ }
+ int cap;
+ cin >> cap;
+ cout << solve(p, n, cap) << endl;
+}

Graph/directed_graph_has_cycle_or_npt.cpp

@@ -49,5 +49,5 @@ int main()
  adj[a].push_back(b);
  adj[b].push_back(a);
  }
- detectCycle(adj, n);
+ cout << detectCycle(adj, n);
 }

Heap/rearranging_characters.cpp

@@ -0,0 +1,25 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+string solve(string s)
+{
+ map<char, int> mp;
+ for (auto j : s)
+ {
+ mp[j]++;
+ }
+ priority_queue<pair<int, char>> pq;
+
+ for (auto j : mp)
+ {
+ pq.push({j.second, j.first});
+ }
+ string result = "";
+}
+
+int main()
+{
+ string s;
+ cin >> s;
+ cout << solve(s);
+}

Tree/tree_and_xor.cpp

@@ -0,0 +1,32 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+int solve(vector<int> &v, vector<vector<int>> &adj, int n)
+{
+}
+
+int main()
+{
+ int t;
+ cin >> t;
+ while (t--)
+ {
+ int n;
+ cin >> n;
+ vector<int> v;
+ for (int i = 0; i < n; i++)
+ {
+ int x;
+ cin >> x;
+ v.push_back(x);
+ }
+ vector<vector<int>> adj(n);
+ for (int i = 0; i < n - 1; i++)
+ {
+ int u, v;
+ cin >> u >> v;
+ adj[u].push_back(v);
+ }
+ int ans = solve(v, adj, n);
+ }
+}