leetcode

Solution to some Leetcode problems written in C++
git clone git://git.dimitrijedobrota.com/leetcode.git
Log | Files | Refs | README | LICENSE
commit a8191073f125dc1c532e676a6ac182a6e9752b83
parent 1572f4d687c5ee888458c3d1dbf643da4dd197c8
author Dimitrije Dobrota <mail@dimitrijedobrota.com>
date Tue, 5 Nov 2024 14:13:32 +0100

5 Random Problems

Diffstat:
A Problems/0390.cpp | ++++++++++++
A Problems/0393.cpp | +++++++++++++++++++++++
A Problems/0395.cpp | ++++++++++++++++++++++++++++++++++
A Problems/0396.cpp | ++++++++++++++++++++
A Problems/0397.cpp | +++++++++++++
M README.md | +++++

6 files changed, 107 insertions(+), 0 deletions(-)

diff --git a/ Problems/0390.cpp b/ Problems/0390.cpp

@@ -0,0 +1,12 @@
class Solution {
public:
int lastRemaining(int n) const {
int head = 1;
for (int step = 1, dir = 1; n > 1; step *= 2, n /= 2, dir = !dir) {
head += dir || n % 2 ? step : 0;
}
return head;
}
};

diff --git a/ Problems/0393.cpp b/ Problems/0393.cpp

@@ -0,0 +1,23 @@
class Solution {
public:
bool validUtf8(const vector<int> &data) const {
static const uint8_t mask[] = {0x80, 0xE0, 0xF0, 0xF8};
static const uint8_t val[] = {0x00, 0xC0, 0xE0, 0xF0};
const int n = size(data);
for (int i = 0, j, k; i < n; i++) {
for (j = 0; j < 4; j++) {
if ((data[i] & mask[j]) != val[j]) continue;
break;
}
if (j == 4) return false;
for (k = 0; k < j && i + 1 < n; k++) {
if ((data[++i] & 0xC0) != 0x80) return false;
}
if (k != j) return false;
}
return true;
}
};

diff --git a/ Problems/0395.cpp b/ Problems/0395.cpp

@@ -0,0 +1,34 @@
class Solution {
public:
int longestSubstring(const string &s, int k) const {
const int n = size(s);
static int count[26];
int res = 0, maxUnique = 0;
memset(count, 0x00, sizeof(count));
for (const char c : s)
maxUnique += !count[c - 'a']++;
for (int l = 1; l <= maxUnique; l++) {
memset(count, 0x00, sizeof(count));
int i = 0, j = 0, unique = 0, least = 0;
while (j < n) {
if (unique <= l) {
unique += !count[s[j] - 'a']++;
least += count[s[j] - 'a'] == k;
j++;
} else {
least -= count[s[i] - 'a'] == k;
unique -= !--count[s[i] - 'a'];
i++;
}
if (unique == l && least == l) {
res = max(res, j - i);
}
}
}
return res;
}
};

diff --git a/ Problems/0396.cpp b/ Problems/0396.cpp

@@ -0,0 +1,20 @@
class Solution {
public:
int maxRotateFunction(const vector<int> &nums) const {
const int n = size(nums);
int sum = 0, crnt = 0;
for (int i = 0; i < n; i++) {
crnt += i * nums[i];
sum += nums[i];
}
int res = crnt;
for (int i = n - 1; i >= 0; i--) {
crnt += sum - nums[i] * n;
res = max(res, crnt);
}
return res;
}
};

diff --git a/ Problems/0397.cpp b/ Problems/0397.cpp

@@ -0,0 +1,13 @@
class Solution {
private:
unordered_map<int, int> visited;
public:
int integerReplacement(int n) {
if (n == 1) return 0;
if (visited.count(n)) return visited[n];
if (!(n & 1 == 1)) return visited[n] = 1 + integerReplacement(n / 2);
return visited[n] = 2 + min(integerReplacement(n / 2), integerReplacement(n / 2 + 1));
}
};

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

@@ -341,8 +341,13 @@ reference and a base for solving problems. | 0387 | Easy | [First Unique Character in a String](Problems/0387.cpp) | | 0388 | Medium | [Longest Absolute File Path](Problems/0388.cpp) | | 0389 | Easy | [Find the Difference](Problems/0389.cpp) |
| 0390 | Medium | [Elimination Game](Problems/0390.cpp) |
| 0392 | Easy | [Is Subsequence](Problems/0392.cpp) |
| 0393 | Medium | [UTF-8 Validation](Problems/0393.cpp) |
| 0394 | Medium | [Decode String](Problems/0394.cpp) |
| 0395 | Medium | [Longest Substring with At Least K Repeating Characters](Problems/0395.cpp) |
| 0396 | Medium | [Rotate Function](Problems/0396.cpp) |
| 0397 | Medium | [Integer Replacement](Problems/0397.cpp) |
| 0398 | Medium | [Random Pick Index](Problems/0398.cpp) | | 0399 | Medium | [Evaluate Division](Problems/0399.cpp) | | 0401 | Easy | [Binary Watch](Problems/0401.cpp) |