leetcode

Algorithm I: Day 11

4 files changed, 70 insertions(+), 0 deletions(-)

diff --git a/ Problems/0046.cpp b/ Problems/0046.cpp

@@ -0,0 +1,25 @@

class Solution {

vector<vector<int>> res;

vector<int> crnt;

vector<bool> seen;

void rec(vector<int> &nums, int n) {

if (n == nums.size()) {

res.push_back(crnt);

return;

}

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

if (seen[i]) continue;

seen[i] = true, crnt.push_back(nums[i]);

rec(nums, n + 1);

seen[i] = false, crnt.pop_back();

}

}

public:

vector<vector<int>> permute(vector<int> &nums) {

seen.resize(nums.size());

rec(nums, 0);

return res;

}

};

diff --git a/ Problems/0077.cpp b/ Problems/0077.cpp

@@ -0,0 +1,21 @@

class Solution {

vector<int> crnt;

vector<vector<int>> res;

void rec(int s, int n, int k) {

if (!k) {

res.push_back(crnt);

return;

}

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

crnt.push_back(i);

rec(i + 1, n, k - 1);

crnt.pop_back();

}

}

public:

vector<vector<int>> combine(int n, int k) {

rec(1, n, k);

return res;

}

};

diff --git a/ Problems/0784.cpp b/ Problems/0784.cpp

@@ -0,0 +1,21 @@

class Solution {

vector<string> res;

void rec(string &s, int st, string crnt) {

while (st < s.size() && !isalpha(s[st])) crnt += s[st++];

if (st == s.size()) {

res.push_back(crnt);

return;

}

char c = tolower(s[st]);

rec(s, st + 1, crnt + c);

rec(s, st + 1, crnt + (char)toupper(c));

}

public:

vector<string> letterCasePermutation(string s) {

rec(s, 0, "");

return res;

}

};

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

@@ -46,6 +46,7 @@ for solving problems. | 0042 | Medium | [Trapping Rain Water](Problems/0011.cpp) | | 0043 | Medium | [Multiply Strings](Problems/0043.cpp) | | 0045 | Medium | [Jump Game II](Problems/0045.cpp) |

| 0046 | Medium | [Permutations](Problems/0046.cpp) |

| 0049 | Medium | [Group Anagrams](Problems/0049.cpp) | | 0053 | Medium | [Maximum Subarray](Problems/0053.cpp) | | 0054 | Medium | [Spiral Matrix](Problems/0054.cpp) |

@@ -59,6 +60,7 @@ for solving problems. | 0067 | Easy | [Add Binary](Problems/0067.cpp) | | 0070 | Easy | [Climbing Stairs](Problems/0070.cpp) | | 0074 | Medium | [Search a 2D Matrix](Problems/0074.cpp) |

| 0077 | Medium | [Combinations](Problems/0077.cpp) |

| 0083 | Easy | [Remove Duplicates from Sorted List](Problems/0083.cpp) | | 0084 | Hard | [Largest Rectangle in Histogram](Problems/0084.cpp) | | 0088 | Easy | [Merge Sorted Array](Problems/0088.cpp) |

@@ -228,6 +230,7 @@ for solving problems. | 0747 | Easy | [Largest Number At Least Twice of Others](Problems/0747.cpp) | | 0752 | Medium | [Open the Lock](Problems/0752.cpp) | | 0783 | Easy | [Minimum Distance Between BST Nodes](Problems/0783.cpp) |

| 0784 | Medium | [Letter Case Permutation](Problems/0784.cpp) |

| 0785 | Medium | [Is Graph Bipartite?](Problems/0785.cpp) | | 0787 | Medium | [Cheapest Flights Within K Stops](Problems/0787.cpp) | | 0797 | Medium | [All Paths From Source to Target](Problems/0797.cpp) |