leetcode

Daily Problem, 1 Random

3 files changed, 86 insertions(+), 0 deletions(-)

diff --git a/ Problems/0336.cpp b/ Problems/0336.cpp

@@ -0,0 +1,66 @@

static bool isPalindrome(const string &s, int i, int j) {

while (i < j) {

if (s[i++] != s[j--]) return false;

}

return true;

}

class Trie {

struct Node {

Node *children[26] = {0};

vector<int> suffix;

int idx = -1;

} root;

public:

void insert(const string &s, int idx) {

Node *crnt = &root;

for (int i = size(s) - 1; i >= 0; i--) {

auto &child = crnt->children[s[i] - 'a'];

if (!child) child = new Node();

if (isPalindrome(s, 0, i)) crnt->suffix.push_back(idx);

crnt = child;

}

crnt->suffix.push_back(idx);

crnt->idx = idx;

}

void query(const string &s, int idx, vector<vector<int>> &res) const {

const Node *crnt = &root;

const int n = size(s);

for (int i = 0; i < n; i++) {

if (crnt->idx != -1 && crnt->idx != idx && isPalindrome(s, i, n - 1)) {

res.push_back({idx, crnt->idx});

}

crnt = crnt->children[s[i] - 'a'];

if (!crnt) return;

}

for (const auto n : crnt->suffix) {

if (n == idx) continue;

res.push_back({idx, n});

}

}

};

class Solution {

public:

vector<vector<int>> palindromePairs(const vector<string> &words) const {

const int n = size(words);

vector<vector<int>> res;

Trie trie;

for (int i = 0; i < n; i++)

trie.insert(words[i], i);

for (int i = 0; i < n; i++)

trie.query(words[i], i, res);

return res;

}

};

diff --git a/ Problems/1957.cpp b/ Problems/1957.cpp

@@ -0,0 +1,18 @@

class Solution {

public:

string makeFancyString(string &s) const {

char prev = '\0';

int i = 0, cnt = 0;

for (const char c : s) {

if (c == prev)

cnt++;

else

prev = c, cnt = 1;

if (cnt <= 2) s[i++] = c;

}

s.resize(i);

return s;

}

};

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

@@ -307,6 +307,7 @@ reference and a base for solving problems. | 0331 | Medium | [Verify Preorder Serialization of a Binary Tree](Problems/0331.cpp) | | 0332 | Hard | [Reconstruct Itinerary](Problems/0332.cpp) | | 0334 | Medium | [Increasing Triplet Subsequence](Problems/0334.cpp) |

| 0336 | Hard | [Palindrome Pairs](Problems/0336.cpp) |

| 0337 | Medium | [House Robber III](Problems/0337.cpp) | | 0338 | Easy | [Counting Bits](Problems/0338.cpp) | | 0341 | Medium | [Flatten Nested List Iterator](Problems/0341.cpp) |

@@ -1105,6 +1106,7 @@ reference and a base for solving problems. | 1945 | Easy | [Sum of Digits of String After Convert](Problems/1945.cpp) | | 1947 | Medium | [Maximum Compatibility Score Sum](Problems/1947.cpp) | | 1954 | Medium | [Minimum Garden Perimeter to Collect Enough Apples](Problems/1954.cpp) |

| 1957 | Easy | [Delete Characters to Make Fancy String](Problems/1957.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) | | 1964 | Hard | [Find the Longest Valid Obstacle Course at Each Position](Problems/1964.cpp) |