leetcode

4 Random Problems

5 files changed, 123 insertions(+), 0 deletions(-)

diff --git a/ Problems/0233.cpp b/ Problems/0233.cpp

@@ -0,0 +1,13 @@

class Solution {

public:

int countDigitOne(int n) const {

int res = 0;

for (long long m = 1; m <= n; m *= 10) {

const int a = n / m, b = n % m;

res += (a + 8) / 10 * m + (a % 10 == 1) * (b + 1);

}

return res;

}

};

diff --git a/ Problems/0275.cpp b/ Problems/0275.cpp

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

class Solution {

public:

int hIndex(const vector<int> &citations) const {

const int n = size(citations);

int low = 0, high = n - 1;

while (low <= high) {

const int mid = low + (high - low) / 2;

if (citations[mid] == n - mid) return citations[mid];

if (citations[mid] > n - mid)

high = mid - 1;

else

low = mid + 1;

}

return n - high - 1;

}

};

diff --git a/ Problems/0282.cpp b/ Problems/0282.cpp

@@ -0,0 +1,52 @@

class Solution {

vector<string> res;

vector<long long> operan;

vector<char> operat;

void rec(long long target, const string &num, int start, long long total, long long prev) {

if (start == size(num)) {

if (total != target) return;

res.push_back(to_string(operan[0]));

for (int i = 0; i < size(operat); i++) {

res.back() += operat[i] + to_string(operan[i + 1]);

}

return;

}

operan.push_back(-1);

operat.push_back('_');

for (long long i = start, crnt = 0; i < size(num); i++) {

operan.back() = crnt = crnt * 10 + num[i] - '0';

operat.back() = '+';

rec(target, num, i + 1, total + crnt, crnt);

operat.back() = '-';

rec(target, num, i + 1, total - crnt, -crnt);

operat.back() = '*';

rec(target, num, i + 1, total + prev * (crnt - 1), prev * crnt);

if (num[start] == '0') break;

}

operan.pop_back();

operat.pop_back();

}

public:

vector<string> addOperators(const string &num, int target) {

operan.push_back(-1);

for (long long i = 0, crnt = 0; i < size(num); i++) {

operan.back() = crnt = crnt * 10 + num[i] - '0';

rec(target, num, i + 1, crnt, crnt);

if (num[0] == '0') break;

}

return res;

}

};

diff --git a/ Problems/0301.cpp b/ Problems/0301.cpp

@@ -0,0 +1,36 @@

class Solution {

unordered_set<string> st;

int maxi = 0;

void rec(const string &s, int idx, const string &crnt, int open, int close) {

if (idx == size(s)) {

if (open != 0) return;

if (size(crnt) > maxi) {

maxi = size(crnt);

st.clear();

}

if (size(crnt) == maxi && !st.count(crnt)) {

st.insert(crnt);

}

return;

}

if (s[idx] == '(') {

if (open + 1 <= close) rec(s, idx + 1, crnt + '(', open + 1, close);

rec(s, idx + 1, crnt, open, close);

} else if (s[idx] == ')') {

if (open > 0) rec(s, idx + 1, crnt + ')', open - 1, close - 1);

rec(s, idx + 1, crnt, open, close);

} else

rec(s, idx + 1, crnt + s[idx], open, close);

}

public:

vector<string> removeInvalidParentheses(const string &s) {

rec(s, 0, "", 0, count(begin(s), end(s), ')'));

return vector(begin(st), end(st));

}

};

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

@@ -247,6 +247,7 @@ for solving problems. | 0229 | Medium | [Majority Element II](Problems/0229.cpp) | | 0231 | Easy | [Power of Two](Problems/0231.cpp) | | 0232 | Easy | [Implement Queue using Stacks](Problems/0232.cpp) |

| 0233 | Hard | [Number of Digit One](Problems/0233.cpp) |

| 0234 | Easy | [Palindrome Linked List](Problems/0234.cpp) | | 0235 | Medium | [Lowest Common Ancestor of a Binary Search Tree](Problems/0235.cpp) | | 0236 | Medium | [Lowest Common Ancestor of a Binary Tree](Problems/0236.cpp) |

@@ -265,8 +266,10 @@ for solving problems. | 0268 | Easy | [Missing Number](Problems/0268.cpp) | | 0273 | Hard | [Integer to English Words](Problems/0273.cpp) | | 0274 | Medium | [H-Index](Problems/0274.cpp) |

| 0275 | Medium | [H-Index II](Problems/0275.cpp) |

| 0278 | Easy | [First Bad Version](Problems/0278.cpp) | | 0279 | Medium | [Perfect Squares](Problems/0279.cpp) |

| 0282 | Hard | [Expression Add Operators](Problems/0282.cpp) |

| 0283 | Easy | [Move Zeroes](Problems/0283.cpp) | | 0284 | Medium | [Peeking Iterator](Problems/0284.cpp) | | 0287 | Medium | [Find the Duplicate Number](Problems/0287.cpp) |

@@ -277,6 +280,7 @@ for solving problems. | 0297 | Hard | [Serialize and Deserialize Binary Tree](Problems/0297.cpp) | | 0299 | Medium | [Bulls and Cows](Problems/0299.cpp) | | 0300 | Medium | [Longest Increasing Subsequence](Problems/0300.cpp) |

| 0301 | Hard | [Remove Invalid Parentheses](Problems/0301.cpp) |

| 0303 | Easy | [Range Sum Query - Immutable](Problems/0303.cpp) | | 0304 | Medium | [Range Sum Query 2D - Immutable](Problems/0304.cpp) | | 0306 | Medium | [Additive Number](Problems/0306.cpp) |