leetcode

Solution to some Leetcode problems written in C++
git clone git://git.dimitrijedobrota.com/leetcode.git
Log | Files | Refs | README | LICENSE |
commit05c8686ed873950ead89360be22fbfb967f6ec82
parent42b1e770bb8cebedeaf32d75ce6cd006b8bb7e3f
authorDimitrije Dobrota <mail@dimitrijedobrota.com>
dateSat, 15 Jul 2023 10:08:54 +0200

Daily Problem

Diffstat:
AProblems/1751.cpp|+++++++++++++++++++++++++++++++++++++++++++++++++++++++++
MREADME.md|+

2 files changed, 58 insertions(+), 0 deletions(-)

diff --git a/Problems/1751.cpp b/Problems/1751.cpp

@@ -0,0 +1,57 @@

// Recursive, top down
class Solution {
typedef vector<int> Event;
vector<vector<int>> dp;
int rec(const vector<Event> &events, const vector<Event>::const_iterator it,
int k) {
static const auto cmp = [](const Event &a, int val) { return a[0] <= val; };
if (!k || it == events.end()) return 0;
int idx = distance(events.begin(), it);
if (dp[k][idx] != -1) return dp[k][idx];
auto next = lower_bound(it, events.end(), (*it)[1], cmp);
int with = (*it)[2] + rec(events, next, k - 1);
int without = rec(events, it + 1, k);
return dp[k][idx] = max(with, without);
}
public:
int maxValue(vector<Event> &events, int k) {
static const auto cmp = [](const Event &a, const Event &b) {
return a[0] < b[0];
};
sort(events.begin(), events.end(), cmp);
dp = vector(k + 1, vector(events.size(), -1));
return rec(events, events.begin(), k);
}
};
// Iterative, bottom up
class Solution {
typedef vector<int> Event;
public:
int maxValue(vector<Event> &events, int k) {
static const auto cmp = [](const Event &a, int val) { return a[0] <= val; };
static const auto cmp_sort = [](const Event &a, const Event &b) {
return a[0] < b[0];
};
sort(events.begin(), events.end(), cmp_sort);
vector<vector<int>> dp(k + 1, vector(events.size() + 1, 0));
auto start = events.rbegin();
for (int i = events.size() - 1; i >= 0; i--, start++) {
auto it = lower_bound(start.base(), events.end(), events[i][1], cmp);
int offset = distance(events.begin(), it);
for (int cnt = 1; cnt <= k; cnt++) {
dp[cnt][i] = max(dp[cnt][i + 1], events[i][2] + dp[cnt - 1][offset]);
}
}
return dp[k][0];
}
};

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

@@ -515,6 +515,7 @@ for solving problems.

| 1721 | Medium | [Swapping Nodes in a Linked List](Problems/1721.cpp) |
| 1722 | Medium | [Minimize Hamming Distance After Swap Operations](Problems/1722.cpp) |
| 1732 | Easy | [Find the Highest Altitude](Problems/1732.cpp) |
| 1751 | Hard | [Maximum Number of Events That Can Be Attended II](Problems/1751.cpp) |
| 1768 | Easy | [Merge Strings Alternately](Problems/1768.cpp) |
| 1786 | Medium | [Number of Restricted Paths From First to Last Node](Problems/1786.cpp) |
| 1791 | Easy | [Find Center of Star Graph](Problems/1791.cpp) |