leetcode

5 Random Problems

6 files changed, 100 insertions(+), 0 deletions(-)

diff --git a/ Problems/0441.cpp b/ Problems/0441.cpp

@@ -0,0 +1,4 @@

class Solution {

public:

int arrangeCoins(int n) const { return (sqrt(8l * n + 1) - 1) / 2; }

};

diff --git a/ Problems/0457.cpp b/ Problems/0457.cpp

@@ -0,0 +1,38 @@

class Solution {

public:

bool circularArrayLoop(vector<int> &nums) const {

const int n = size(nums);

static int seen[5001];

const auto next = [&](int k) {

const int res = (k + nums[k] % n + n) % n;

seen[res] = true;

return res;

};

memset(seen, 0x00, sizeof(seen));

for (auto &num : nums)

num %= n;

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

if (seen[i]) continue;

int t = i, h = i;

do {

t = next(t);

h = next(next(h));

} while (t != h);

const bool dir = nums[t] > 0;

do {

t = next(t);

if ((nums[t] > 0) != dir) goto next;

} while (t != h);

if ((t + nums[t] + n) % n != t) return true;

next:;

}

return false;

}

};

diff --git a/ Problems/0461.cpp b/ Problems/0461.cpp

@@ -0,0 +1,4 @@

class Solution {

public:

int hammingDistance(unsigned x, unsigned y) const { return popcount(x ^ y); }

};

diff --git a/ Problems/0464.cpp b/ Problems/0464.cpp

@@ -0,0 +1,32 @@

class Solution {

static int8_t dp[1 << 20];

int rec(int maxi, int tgt, int k) {

if (dp[k] != 0) return dp[k] > 0;

if (tgt <= 0) return false;

for (int i = 1, mask = 1; i <= maxi; mask <<= 1, i++) {

if (k & mask) continue;

if (rec(maxi, tgt - i, k | mask)) continue;

dp[k] = 1;

return true;

}

dp[k] = -1;

return false;

}

public:

bool canIWin(int maxi, int tgt) {

if (tgt <= maxi) return true;

const int sum = maxi * (maxi + 1) / 2;

if (sum < tgt) return false;

if (sum == tgt) return maxi % 2;

memset(dp, 0x00, sizeof(dp));

return rec(maxi, tgt, 0);

}

};

int8_t Solution::dp[1 << 20];

diff --git a/ Problems/0467.cpp b/ Problems/0467.cpp

@@ -0,0 +1,17 @@

class Solution {

public:

int findSubstringInWraproundString(const string &s) const {

const int n = size(s);

static int seen[26];

memset(seen, 0x00, sizeof(seen));

for (const char c : s)

seen[c - 'a'] = 1;

for (int i = 1, cnt = 1; i < n; i++) {

cnt = (s[i] - s[i - 1] + 26) % 26 == 1 ? cnt + 1 : 1;

seen[s[i] - 'a'] = max(seen[s[i] - 'a'], cnt);

}

return accumulate(seen, seen + 26, 0);

}

};

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

@@ -377,6 +377,7 @@ reference and a base for solving problems. | 0437 | Medium | [Path Sum III](Problems/0437.cpp) | | 0438 | Medium | [Find All Anagrams in a String](Problems/0438.cpp) | | 0440 | Hard | [K-th Smallest in Lexicographical Order](Problems/0440.cpp) |

| 0441 | Easy | [Arranging Coins](Problems/0441.cpp) |

| 0442 | Medium | [Find All Duplicates in an Array](Problems/0442.cpp) | | 0443 | Medium | [String Compression](Problems/0443.cpp) | | 0445 | Medium | [Add Two Numbers II](Problems/0445.cpp) |

@@ -391,11 +392,15 @@ reference and a base for solving problems. | 0454 | Medium | [4Sum II](Problems/0454.cpp) | | 0455 | Easy | [Assign Cookies](Problems/0455.cpp) | | 0456 | Medium | [132 Pattern](Problems/0456.cpp) |

| 0457 | Medium | [Circular Array Loop](Problems/0457.cpp) |

| 0458 | Hard | [Poor Pigs](Problems/0458.cpp) | | 0459 | Easy | [Repeated Substring Pattern](Problems/0459.cpp) | | 0460 | Hard | [LFU Cache](Problems/0460.cpp) |

| 0461 | Easy | [Hamming Distance](Problems/0461.cpp) |

| 0462 | Medium | [Minimum Moves to Equal Array Elements II](Problems/0462.cpp) | | 0463 | Easy | [Island Perimeter](Problems/0463.cpp) |

| 0464 | Medium | [Can I Win](Problems/0464.cpp) |

| 0467 | Medium | [Unique Substrings in Wraparound String](Problems/0467.cpp) |

| 0472 | Hard | [Concatenated Words](Problems/0472.cpp) | | 0476 | Easy | [Number Complement](Problems/0476.cpp) | | 0477 | Medium | [Total Hamming Distance](Problems/0477.cpp) |