leetcode

Solution to some Leetcode problems written in C++
git clone git://git.dimitrijedobrota.com/leetcode.git
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commit a958ff5dc52c59f758b36477694d692b4e3b3b61
parent cc659873f5697b32e5a17eeca6cef8d7116216c4
author Dimitrije Dobrota < mail@dimitrijedobrota.com >
date Tue, 30 Jan 2024 21:27:07 +0000

2 Random Problems

Diffstat:
A Problems/0930.cpp | +++++++++++++++++++++++++++++++++++++
A Problems/2201.cpp | ++++++++++++++++++++++++++++++
M README.md | ++

3 files changed, 69 insertions(+), 0 deletions(-)

diff --git a/ Problems/0930.cpp b/ Problems/0930.cpp

@@ -0,0 +1,37 @@

class Solution {
public:
int numSubarraysWithSum(const vector<int> &nums, int goal) const {
unordered_map<int, int> um = {{0, 1}};
int res = 0, crnt = 0;

for (const int n : nums) {
crnt += n;
res += um[crnt - goal];
um[crnt]++;
}

return res;
}
};

// O(1) space
class Solution {
int atMost(const vector<int> &nums, int goal) const {
if (goal < 0) return 0;

int res = 0, crnt = 0, i = 0;
for (int j = 0; j < size(nums); j++) {
goal -= nums[j];
while (goal < 0)
goal += nums[i++];
res += j - i + 1;
}

return res;
}

public:
int numSubarraysWithSum(const vector<int> &nums, int goal) const {
return atMost(nums, goal) - atMost(nums, goal - 1);
}
};

diff --git a/ Problems/2201.cpp b/ Problems/2201.cpp

@@ -0,0 +1,30 @@

class Solution {
public:
int digArtifacts(int n, const vector<vector<int>> &artifacts, const vector<vector<int>> &dig) const {
vector<vector<int>> grid(n, vector(n, 0));
for (const auto &d : dig)
grid[d[0]][d[1]] = 1;

for (int i = 0, acc = 0; i < n; i++)
grid[i][0] = acc += grid[i][0];
for (int i = 0, acc = 0; i < n; i++)
grid[0][i] = acc += grid[0][i];
for (int i = 1; i < n; i++) {
for (int j = 1; j < n; j++) {
grid[i][j] += grid[i - 1][j] + grid[i][j - 1] - grid[i - 1][j - 1];
}
}

int res = 0;
for (const auto &art : artifacts) {
const int goal = (art[2] - art[0] + 1) * (art[3] - art[1] + 1);
int crnt = grid[art[2]][art[3]];
crnt -= art[0] > 0 ? grid[art[0] - 1][art[3]] : 0;
crnt -= art[1] > 0 ? grid[art[2]][art[1] - 1] : 0;
crnt += art[0] > 0 && art[1] > 0 ? grid[art[0] - 1][art[1] - 1] : 0;
res += goal == crnt;
}

return res;
}
};

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

@@ -531,6 +531,7 @@ for solving problems.

| 0920 | Hard | [Number of Music Playlists](Problems/0920.cpp) |
| 0921 | Medium | [Minimum Add to Make Parentheses Valid](Problems/0921.cpp) |
| 0926 | Medium | [Flip String to Monotone Increasing](Problems/0926.cpp) |
| 0930 | Medium | [Binary Subarrays With Sum](Problems/0930.cpp) |
| 0931 | Medium | [Minimum Falling Path Sum](Problems/0931.cpp) |
| 0932 | Medium | [Beautiful Array](Problems/0932.cpp) |
| 0933 | Easy | [Number of Recent Calls](Problems/0933.cpp) |

@@ -976,6 +977,7 @@ for solving problems.

| 2187 | Medium | [Minimum Time to Complete Trips](Problems/2187.cpp) |
| 2192 | Medium | [All Ancestors of a Node in a Directed Acyclic Graph](Problems/2192.cpp) |
| 2196 | Medium | [Create Binary Tree From Descriptions](Problems/2196.cpp) |
| 2201 | Medium | [Count Artifacts That Can Be Extracted](Problems/2201.cpp) |
| 2215 | Easy | [Find the Difference of Two Arrays](Problems/2215.cpp) |
| 2218 | Hard | [Maximum Value of K Coins From Piles](Problems/2218.cpp) |
| 2221 | Medium | [Find Triangular Sum of an Array](Problems/2221.cpp) |