leetcode

Solution to some Leetcode problems written in C++
git clone git://git.dimitrijedobrota.com/leetcode.git
Log | Files | Refs | README | LICENSE
commit 226177df321c7e565875051333a4322b49ddf5b6
parent a1f043c44f6e2870178ff62025f2c3dce5a09932
author Dimitrije Dobrota < mail@dimitrijedobrota.com >
date Tue, 14 Nov 2023 21:30:43 +0000

Daily Problem

Diffstat:
A Problems/1930.cpp | +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
M README.md | +

2 files changed, 62 insertions(+), 0 deletions(-)

diff --git a/ Problems/1930.cpp b/ Problems/1930.cpp

@@ -0,0 +1,61 @@

class Solution {
public:
int countPalindromicSubsequence(const string &s) const {
static pair<int, int> pos[27];
memset(pos, 0xFF, sizeof(pos));

const int n = s.size();
for (int i = 0; i < n; i++) {
const int idx = s[i] & 0x1F;
if (pos[idx].first == -1) pos[idx].first = i;
pos[idx].second = i;
}

int res = 0;
for (int i = 1; i <= 26; i++) {
const auto [first, last] = pos[i];
if (first == -1) continue;
bitset<27> bs;
for (int j = first + 1; j < last; j++)
bs.set(s[j] & 0x1F);
res += bs.count();
}
return res;
}
};

// Improve constant factor by using a lot of memory
class Solution {
public:
int countPalindromicSubsequence(const string &s) const {
static int count[100001][27];
memset(count, 0x00, sizeof(int) * 27);

static pair<int, int> pos[27];
memset(pos, 0xFF, sizeof(pos));

const int n = s.size();
for (int i = 0; i < n; i++) {
const int idx = s[i] & 0x1F;
if (i != 0) memcpy(count[i], count[i - 1], sizeof(int) * 27);
count[i][idx]++;

if (pos[idx].first == -1) pos[idx].first = i;
pos[idx].second = i;
}

int res = 0;
for (int i = 1; i <= 26; i++) {
const auto [first, last] = pos[i];
if (first == -1) continue;

count[last][i]--;
for (int j = 1; j <= 26; j++) {
res += count[last][j] > count[first][j];
}
count[last][i]++;
}

return res;
}
};

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

@@ -755,6 +755,7 @@ for solving problems.

| 1910 | Medium | [Remove All Occurrences of a Substring](Problems/1910.cpp) |
| 1921 | Medium | [Eliminate Maximum Number of Monsters](Problems/1921.cpp) |
| 1926 | Medium | [Nearest Exit from Entrance in Maze](Problems/1926.cpp) |
| 1930 | Medium | [Unique Length-3 Palindromic Subsequences](Problems/1930.cpp) |
| 1947 | Medium | [Maximum Compatibility Score Sum](Problems/1947.cpp) |
| 1962 | Medium | [Remove Stones to Minimize the Total](Problems/1962.cpp) |
| 1963 | Medium | [Minimum Number of Swaps to Make the String Balanced](Problems/1963.cpp) |