leetcode

Solution to some Leetcode problems written in C++
git clone git://git.dimitrijedobrota.com/leetcode.git
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commit30cb3fa1b382e513024b3f6c934a0f7d9fbbddd2
parent5c32b2fa0cd72bc58ac2cd561385f566a835f328
authorDimitrije Dobrota <mail@dimitrijedobrota.com>
dateFri, 10 Feb 2023 14:55:36 +0100

LeetCode 75 II: Day 7

Diffstat:
AProblems/0437.cpp|++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
MREADME.md|+

2 files changed, 71 insertions(+), 0 deletions(-)

diff --git a/Problems/0437.cpp b/Problems/0437.cpp

@@ -0,0 +1,70 @@

// Brute force
class Solution {
public:
int pathSum(TreeNode *root, int targetSum) {
if (!root) return 0;
stack<TreeNode *> st;
queue<TreeNode *> q;
st.push(root);
while (!st.empty()) {
TreeNode *root = st.top();
st.pop();
q.push(root);
if (root->left) st.push(root->left);
if (root->right) st.push(root->right);
}
int res = 0;
while (!q.empty()) {
stack<pair<TreeNode *, long long>> st;
st.push({q.front(), 0});
q.pop();
while (!st.empty()) {
auto [root, sum] = st.top();
st.pop();
sum += root->val;
if (sum == targetSum) res++;
if (root->left) st.push({root->left, sum});
if (root->right) st.push({root->right, sum});
}
}
return res;
}
};
// Optimized
class Solution {
public:
int pathSum(TreeNode *root, int targetSum) {
if (!root) return 0;
queue<pair<TreeNode *, vector<long long>>> q;
int res = 0;
q.push({root, {}});
while (!q.empty()) {
auto &[root, vec] = q.front();
long long sum = root->val + (vec.size() ? vec.back() : 0);
for (int num : vec)
if (sum - num == targetSum) res++;
if (sum == targetSum) res++;
if (root->left) {
q.push({root->left, vec});
q.back().second.push_back(sum);
}
if (root->right) {
q.push({root->right, vec});
q.back().second.push_back(sum);
}
q.pop();
}
return res;
}
};

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

@@ -209,6 +209,7 @@ for solving problems.

| 0430 | Medium | [Flatten a Multilevel Doubly Linked list](Problems/0430.cpp) |
| 0433 | Medium | [Minimum Genetic Mutation](Problems/0433.cpp) |
| 0435 | Medium | [Non-overlapping Intervals](Problems/0435.cpp) |
| 0437 | Medium | [Path Sum III](Problems/0437.cpp) |
| 0438 | Medium | [Find All Anagrams in a String](Problems/0438.cpp) |
| 0445 | Medium | [Add Two Numbers II](Problems/0445.cpp) |
| 0448 | Easy | [Find All Numbers Disappeared in an Array](Problems/0448.cpp) |