leetcode

Solution to some Leetcode problems written in C++
git clone git://git.dimitrijedobrota.com/leetcode.git
Log | Files | Refs | README | LICENSE |
commita4868eb2e020dacfffda0b45b4605ed2c425dcea
parent0c45af7adbc5c6cabca3ed186b0a6640b75d1c46
authorDimitrije Dobrota <mail@dimitrijedobrota.com>
dateSun, 15 Jan 2023 14:51:54 +0100

Daily Problem

Diffstat:
AProblems/2421.cpp|++++++++++++++++++++++++++++++++++++++++++++++++++++++
MREADME.md|+

2 files changed, 55 insertions(+), 0 deletions(-)

diff --git a/Problems/2421.cpp b/Problems/2421.cpp

@@ -0,0 +1,54 @@

class UnionFind {
int n, cnt = n;
vector<int> root, size;
public:
UnionFind(int n) : n(n), root(n), size(n, 1) {
iota(root.begin(), root.end(), 0);
}
int find(int x) {
while (x != root[x]) x = root[x] = root[root[x]];
return x;
}
void join(int x, int y) {
x = find(x), y = find(y);
if (x != y) {
if (size[x] > size[y]) swap(x, y);
root[x] = y;
size[y] += size[x];
cnt--;
}
}
};
class Solution {
public:
int numberOfGoodPaths(vector<int> &vals, vector<vector<int>> &edges) {
int n = vals.size();
map<int, vector<int>> valuesToNodes;
vector<vector<int>> adj(n);
UnionFind uf(n);
for (auto &edge : edges) {
adj[edge[0]].push_back(edge[1]);
adj[edge[1]].push_back(edge[0]);
}
for (int i = 0; i < n; i++) valuesToNodes[vals[i]].push_back(i);
int goodPaths = 0;
for (auto &[value, nodes] : valuesToNodes) {
for (int node : nodes) {
for (int neighbor : adj[node]) {
if (vals[node] >= vals[neighbor]) { uf.join(node, neighbor); }
}
}
unordered_map<int, int> group;
for (int u : nodes) group[uf.find(u)]++;
for (auto &[_, size] : group) goodPaths += (size * (size + 1) / 2);
}
return goodPaths;
}
};

diff --git a/README.md b/README.md

@@ -309,6 +309,7 @@ for solving problems.

| 2368 | Medium | [Reachable Nodes With Restrictions](Problems/2368.cpp) |
| 2374 | Medium | [Node With Highest Edge Score](Problems/2374.cpp) |
| 2390 | Medium | [Removing Stars From a String](Problems/2390.cpp) |
| 2421 | Medium | [Number of Good Paths](Problems/2421.cpp) |
| 2461 | Medium | [Maximum Sum of Distinct Subarrays With Length K](Problems/2461.cpp) |
| 2465 | Easy | [Number of Distinct Averages](Problems/2465.cpp) |
| 2466 | Medium | [Count Ways To Build Good Strings](Problems/2466.cpp) |