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Original file line number Diff line number Diff line change
Expand Up @@ -119,6 +119,51 @@ tags:
#### C++

```cpp
uint32_t dists[15000];
uint16_t nxt[15000];

class Solution {
public:
int maxDistance(int s, vector<vector<int>>& points, int k) {
const uint64_t n = points.size(), perim = 4UL * s;

for (uint i = 0; i < n; i++) {
uint64_t x = points[i][0], y = points[i][1];
dists[i] = (x == 0 || y == s) ? perim - x - y : x + y;
}

sort(dists, dists + n);

const auto check = [&](uint64_t x) -> bool {
for (uint i = 0, r = 0; i < n; i++) {
r = max(r, i + 1);
while (r < n && dists[r] < dists[i] + x) r++;
nxt[i] = r;
}
uint64_t maxreach = dists[n - 1] + perim - (k - 1) * x;
auto limit = perim - x;

for (uint i = 0; i < n && dists[i] <= maxreach; i++) {
uint j = i;
for (uint r = k - 1; r > 0 && j != n; r--) {
j = nxt[j];
}
if (j != n && dists[j] - dists[i] <= limit) return true;
}
return false;
};

uint64_t lo = 1, hi = perim / k;
while (lo < hi) {
auto x = (lo + hi + 1) / 2;
if (check(x))
lo = x;
else
hi = x - 1;
}
return hi;
}
};

```

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Original file line number Diff line number Diff line change
Expand Up @@ -97,7 +97,44 @@ tags:
#### C++

```cpp

class Solution {
public:
int uniqueXorTriplets(vector<int>& nums) {
const int SIZE = 2048; // since nums[i] <= 1500 < 2048, all XORs fit in 11 bits

vector<bool> present(SIZE, false);
for (int v : nums) present[v] = true;

vector<int> distinct;
for (int v = 0; v < SIZE; v++) {
if (present[v]) distinct.push_back(v);
}

// Step 1: compute all possible pairwise XORs (a ^ b)
vector<bool> pairXor(SIZE, false);
for (int a : distinct) {
for (int b : distinct) {
pairXor[a ^ b] = true;
}
}

// Step 2: compute all possible triple XORs (s ^ c) where s is from pairXor set
vector<bool> tripleXor(SIZE, false);
for (int s = 0; s < SIZE; s++) {
if (!pairXor[s]) continue;
for (int c : distinct) {
tripleXor[s ^ c] = true;
}
}

int count = 0;
for (int i = 0; i < SIZE; i++) {
if (tripleXor[i]) count++;
}

return count;
}
};
```

#### Go
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -121,6 +121,96 @@ tags:
#### C++

```cpp
long long comb(long long n, long long m, long long k) {
long long res = 1;
if (n - m < m) {
m = n - m;
}

for (long long i = 1; i <= m; i++) {
res = res * (n - i + 1) / i;
if (res > k) {
return k + 1;
}
}
return res;
}

long long permutations(int rem, int* bucket, long long k) {
long long ways = 1;
for (int i = 0; i < 26; i++) {
if (bucket[i] == 0) {
continue;
}

ways *= comb(rem, bucket[i], k);
if (ways > k) {
break;
}
rem -= bucket[i];
}
return ways;
}

char* smallestPalindrome(char* s, long long k) {
int len = strlen(s);
int partition = len / 2;
int bucket[26] = {0};

for (int i = 0; i < partition; i++) {
bucket[s[i] - 'a'] += 1;
}

char* left = (char*)malloc(partition + 1);
int left_idx = 0;
long long start_index = 1;

for (int pos = 0; pos < partition; pos++) {
for (int i = 0; i < 26; i++) {
if (bucket[i] == 0) {
continue;
}

bucket[i] -= 1;

long long ways = permutations(partition - pos - 1, bucket, k);
if (start_index + ways > k) {
left[left_idx++] = i + 'a';
break;
}

bucket[i] += 1;
start_index += ways;
}
}
left[left_idx] = '\0';

if (left_idx < partition) {
char* empty_res = (char*)malloc(1);
empty_res[0] = '\0';
free(left);
return empty_res;
}

char* result = (char*)malloc(len + 1);
int res_idx = 0;

for (int i = 0; i < partition; i++) {
result[res_idx++] = left[i];
}

if (len % 2 != 0) {
result[res_idx++] = s[partition];
}

for (int i = partition - 1; i >= 0; i--) {
result[res_idx++] = left[i];
}
result[res_idx] = '\0';

free(left);
return result;
}

```

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Original file line number Diff line number Diff line change
Expand Up @@ -229,6 +229,45 @@ tags:
#### C++

```cpp
class Solution {
public:
char processStr(string s, long long k) {
long long len = 0;
for (char c : s) {
if (islower(c)) {
len++;
}
else if (c == '*') {
if (len > 0) len--;
}
else if (c == '#') {
len *= 2;
}
else if (c == '%') {}
}
if (k >= len) return '.';
for (int i = s.size() - 1; i >= 0; i--) {
char c = s[i];
if (islower(c)) {
if (k == len - 1) {
return c;
}
len--;
}
else if (c == '*') {
len++;
}
else if (c == '#') {
len /= 2;
k %= len;
}
else if (c == '%') {
k = len - 1 - k;
}
}
return '.';
}
};

```

Expand Down
Original file line number Diff line number Diff line change
@@ -0,0 +1,79 @@
#include <bits/stdc++.h>
using namespace std;

class Solution {
static constexpr int MOD = 1000000007;

long long modpow(long long a, long long e) {
long long r = 1 % MOD;
a %= MOD;
while (e > 0) {
if (e & 1) r = (r * a) % MOD;
a = (a * a) % MOD;
e >>= 1;
}
return r;
}

public:
int xorAfterQueries(vector<int>& nums, vector<vector<int>>& queries) {
int n = nums.size();
int B = std::sqrt(n) + 1;

vector<vector<vector<pair<int,int>>>> events(B + 1);
for (int k = 1; k <= B; ++k)
events[k].resize(k);

for (auto &qq : queries) {
int l = qq[0], r = qq[1], k = qq[2], v = qq[3];
if (k > B) {
for (int idx = l; idx <= r; idx += k)
nums[idx] = (long long)nums[idx] * v % MOD;
} else {
int res = l % k;
int t1 = (l - res) / k;
int t2 = (r - res) / k;
events[k][res].push_back({t1, v});

if (t2 + 1 <= (n - 1 - res) / k) {
int invv = modpow(v, MOD - 2);
events[k][res].push_back({t2 + 1, invv});
}
}
}

for (int k = 1; k <= B; ++k)
for (int res = 0; res < k; ++res) {
auto &ev = events[k][res];
if (ev.empty())
continue;

sort(ev.begin(), ev.end());
vector<pair<int,int>> comp;

for (auto &p : ev) {
if (!comp.empty() && comp.back().first == p.first)
comp.back().second = (long long)comp.back().second * p.second % MOD;
else
comp.push_back(p);
}

long long cur = 1;
int ptr = 0;
int t = 0;
for (int idx = res; idx < n; idx += k, ++t) {
while (ptr < comp.size() && comp[ptr].first == t) {
cur = (cur * comp[ptr].second) % MOD;
++ptr;
}
nums[idx] = nums[idx] * cur % MOD;
}
}

int xr = 0;
for (int x : nums)
xr ^= x;

return xr;
}
};
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