leetcode

3 Random Problems

4 files changed, 54 insertions(+), 1 deletions(-)

diff --git a/ Problems/0032.cpp b/ Problems/0032.cpp

@@ -0,0 +1,22 @@

class Solution {

public:

int longestValidParentheses(const string &s) const {

stack<int> st;

st.push(-1);

int res = 0;

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

if (s[i] == '(')

st.push(i);

else {

if (!st.empty()) st.pop();

if (!st.empty())

res = max(res, i - st.top());

else

st.push(i);

}

}

return res;

}

};

diff --git a/ Problems/0041.cpp b/ Problems/0041.cpp

@@ -0,0 +1,15 @@

class Solution {

public:

int firstMissingPositive(vector<int> &nums) const {

const int n = size(nums);

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

if (nums[i] <= 0) nums[i] = n + 1;

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

const int num = abs(nums[i]);

if (num <= n) nums[num - 1] = -abs(nums[num - 1]);

}

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

if (nums[i] > 0) return i + 1;

return n + 1;

}

};

diff --git a/ Problems/0790.cpp b/ Problems/0790.cpp

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

class Solution {

public:

int numTilings(int n) const {

static const int MOD = 1E9 + 7;

static long long dp[1001] = {0, 1, 2, 5};

memset(dp + 4, 0x00, sizeof(dp) - 16);

if (n <= 3) return dp[n];

for (int i = 4; i <= n; i++) {

dp[i] = (2 * dp[i - 1] + dp[i - 3]) % MOD;

}

return dp[n];

}

};

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

@@ -54,6 +54,7 @@ for solving problems. | 0028 | Medium | [Find the Index of the First Occurrence in a String](Problems/0028.cpp) | | 0029 | Medium | [Divide Two Integers](Problems/0029.cpp) | | 0031 | Medium | [Next Permutation](Problems/0031.cpp) |

| 0032 | Hard | [Longest Valid Parentheses](Problems/0032.cpp) |

| 0033 | Medium | [Search in Rotated Sorted Array](Problems/0033.cpp) | | 0034 | Medium | [Find First and Last Position of Element in Sorted Array](Problems/0034.cpp) | | 0035 | Easy | [Search Insert Position](Problems/0035.cpp) |

@@ -62,6 +63,7 @@ for solving problems. | 0038 | Medium | [Count and Say](Problems/0038.cpp) | | 0039 | Medium | [Combination Sum](Problems/0039.cpp) | | 0040 | Medium | [Combination Sum II](Problems/0040.cpp) |

| 0041 | Hard | [First Missing Positive](Problems/0041.cpp) |

| 0042 | Medium | [Trapping Rain Water](Problems/0011.cpp) | | 0043 | Medium | [Multiply Strings](Problems/0043.cpp) | | 0044 | Hard | [Wildcard Matching](Problems/0044.cpp) |

@@ -375,7 +377,7 @@ for solving problems. | 0601 | Hard | [Human Traffic of Stadium](Problems/0601.cpp) | | 0602 | Medium | [Friend Requests II: Who Has the Most Friends](Problems/0602.cpp) | | 0605 | Easy | [Can Place Flowers](Problems/0605.cpp) |

| 0606 | Easy | [Construct String from Binary Tree](Problems/0606.cpp) |

| 0606 | Easy | [Construct String from Binary Tree](Problems/0606.cpp) |

| 0607 | Easy | [Sales Person](Problems/0607.cpp) | | 0608 | Medium | [Tree Node](Problems/0608.cpp) | | 0609 | Medium | [Find Duplicate File in System](Problems/0609.cpp) |

@@ -437,6 +439,7 @@ for solving problems. | 0785 | Medium | [Is Graph Bipartite?](Problems/0785.cpp) | | 0787 | Medium | [Cheapest Flights Within K Stops](Problems/0787.cpp) | | 0789 | Medium | [Escape The Ghosts](Problems/0789.cpp) |

| 0790 | Medium | [Domino and Tromino Tiling](Problems/0790.cpp) |

| 0791 | Medium | [Custom Sort String](Problems/0791.cpp) | | 0797 | Medium | [All Paths From Source to Target](Problems/0797.cpp) | | 0799 | Medium | [Champagne Tower](Problems/0799.cpp) |