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replace-question-marks-in-string-to-minimize-its-value.cpp
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replace-question-marks-in-string-to-minimize-its-value.cpp
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// Time: O(n + 26 * log(26))
// Space: O(26)
// greedy, counting sort, prefix sum
class Solution {
public:
string minimizeStringValue(string s) {
const auto& counting_sort = [](const auto& cnt) {
vector<int> result(accumulate(cbegin(cnt), cend(cnt), 0));
for (int i = 0, j = 0; i < size(cnt); ++i) {
for (int _ = 0; _ < cnt[i]; ++_) {
result[j++] = i;
}
}
return result;
};
const auto& fill = [&](const auto& cnt) {
vector<int> result(26);
vector<pair<int, int>> pairs(size(cnt));
for (int i = 0; i < size(cnt); ++i) {
pairs[i] = {cnt[i], i};
}
sort(begin(pairs), end(pairs));
const int total = count(cbegin(s), cend(s), '?');
int curr = 0, i = 0;
for (; i + 1 < size(pairs); ++i) {
if (curr + (pairs[i + 1].first - pairs[i].first) * (i + 1) > total) {
break;
}
curr += (pairs[i + 1].first - pairs[i].first) * (i + 1);
}
const int q = (total - curr) / (i + 1);
const int r = (total - curr) % (i + 1);
for (int j = 0; j <= i; ++j) {
result[pairs[j].second] = (pairs[i].first - pairs[j].first) + q;
}
vector<int> cnt2(26);
for (int j = 0; j <= i; ++j) {
++cnt2[pairs[j].second];
}
const auto& idxs = counting_sort(cnt2);
for (int _ = 0, j = 0; _ < r; ++_) {
++result[idxs[j++]];
}
return result;
};
vector<int> cnt(26);
for (const auto& x : s) {
if (x == '?') {
continue;
}
++cnt[x - 'a'];
}
const auto& idxs = counting_sort(fill(cnt));
int i = 0;
for (auto& x : s) {
if (x != '?') {
continue;
}
x = 'a' + idxs[i++];
}
return s;
}
};
// Time: O(n + n * log(26))
// Space: O(26)
// greedy, counting sort, heap
class Solution2 {
public:
string minimizeStringValue(string s) {
const auto& counting_sort = [](const auto& cnt) {
vector<int> result(accumulate(cbegin(cnt), cend(cnt), 0));
for (int i = 0, j = 0; i < size(cnt); ++i) {
for (int _ = 0; _ < cnt[i]; ++_) {
result[j++] = i;
}
}
return result;
};
vector<int> cnt(26);
for (const auto& x : s) {
if (x == '?') {
continue;
}
++cnt[x - 'a'];
}
vector<pair<int, int>> pairs(size(cnt));
for (int i = 0; i < size(cnt); ++i) {
pairs[i] = {cnt[i], i};
}
priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> min_heap(cbegin(pairs), cend(pairs));
vector<int> cnt2(26);
const int total = count(cbegin(s), cend(s), '?');
for (int _ = 0; _ < total; ++_) {
const auto [c, i] = min_heap.top(); min_heap.pop();
++cnt2[i];
min_heap.emplace(c + 1, i);
}
const auto& idxs = counting_sort(cnt2);
int i = 0;
for (auto& x : s) {
if (x != '?') {
continue;
}
x = 'a' + idxs[i++];
}
return s;
}
};
// Time: O(n + n * 26)
// Space: O(26)
// greedy, counting sort
class Solution3 {
public:
string minimizeStringValue(string s) {
const auto& counting_sort = [](const auto& cnt) {
vector<int> result(accumulate(cbegin(cnt), cend(cnt), 0));
for (int i = 0, j = 0; i < size(cnt); ++i) {
for (int _ = 0; _ < cnt[i]; ++_) {
result[j++] = i;
}
}
return result;
};
vector<int> cnt(26);
for (const auto& x : s) {
if (x == '?') {
continue;
}
++cnt[x - 'a'];
}
vector<int> cnt2(26);
const int total = count(cbegin(s), cend(s), '?');
for (int _ = 0; _ < total; ++_) {
int min_i = 0;
for (int i = 0; i < size(cnt); ++i) {
if (cnt[min_i] + cnt2[min_i] > cnt[i] + cnt2[i]) {
min_i = i;
}
}
++cnt2[min_i];
}
const auto& idxs = counting_sort(cnt2);
int i = 0;
for (auto& x : s) {
if (x != '?') {
continue;
}
x = 'a' + idxs[i++];
}
return s;
}
};