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‎leetcode/1494/0.in‎

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5
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[[2,1],[3,1],[4,1],[1,5]]
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2
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00000
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00110
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00000
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00000
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01000
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0
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0
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1
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0

‎leetcode/1494/comb.cpp‎

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/// http://rosettacode.org/wiki/Combinations#C.2B.2B
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#include <algorithm>
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#include <iostream>
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#include <string>
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void comb(int N, int K)
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{
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std::string bitmask(K, 1); // K leading 1's
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bitmask.resize(N, 0); // N-K trailing 0's
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// print integers and permute bitmask
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do {
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for (int i = 0; i < N; ++i) // [0..N-1] integers
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{
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if (bitmask[i]) std::cout << " " << i;
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}
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std::cout << std::endl;
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} while (std::prev_permutation(bitmask.begin(), bitmask.end()));
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}
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int main()
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{
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comb(5, 3);
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}

‎leetcode/1494/main.cpp‎

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/*
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author: [email protected]
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*/
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#include <bits/stdc++.h>
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#include "../../lib/LeetCodeInput.hpp"
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#include "solution-2.cpp"
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using namespace std;
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int main()
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{
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LeetCodeInput li("0.in");
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vector<vector<int>> mat_1 = li.get_vvi(1);
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// vector<int> arr_1 = li.get_vi(0);
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int num_1 = li.get_i(0);
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int num_2 = li.get_i(2);
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// string s_1 = li.get_s(0);
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chrono::steady_clock::time_point begin = chrono::steady_clock::now();
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Solution solution;
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auto output = solution.minNumberOfSemesters(num_1, mat_1, num_2);
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chrono::steady_clock::time_point end = chrono::steady_clock::now();
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cout << "Time difference = " << chrono::duration_cast<chrono::microseconds> (end - begin).count() << "µs" << endl;
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cout << output << endl;
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// for (int i: output){
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// cout << i << ' ';
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// }
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// for (auto i: output){
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// for (int j: i){
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// cout << j << ' ';
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// }
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// cout << '\n';
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// }
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return 0;
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}

‎leetcode/1494/solution-2.cpp‎

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/*
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author: [email protected]
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time: O()
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space: O()
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Runtime: 22 ms, faster than 100.00% of C++ online submissions for Parallel Courses II.
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Memory Usage: 8.4 MB, less than 88.21% of C++ online submissions for Parallel Courses II.
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reference: leetcoe 26ms solution
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dfs
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*/
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#include <bits/stdc++.h>
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using namespace std;
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#define all(x) begin(x), end(x)
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typedef vector<int> vi;
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typedef vector<vector<int>> vvi;
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class Solution {
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public:
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int N , K;
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vector<vector<int>> graph;
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int indegree[15];
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int finalBitMask;
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int dp[(1 << 15) + 1];
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int solve(int bitMask) {
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if (bitMask == finalBitMask) return 0;
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if (dp[bitMask] != -1) return dp[bitMask];
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memset(indegree, 0, sizeof(indegree));
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for (int i = 0; i < N; i++) {
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if (!(bitMask & (1 << i))) {
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for (int v : graph[i]) {
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indegree[v]++;
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}
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}
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}
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int availMask = 0;
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for (int i = 0; i < N; i++) {
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if (!(bitMask & (1 << i)) && indegree[i] == 0) availMask |= (1 << i);
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}
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// before doing this check for the case where number of available courses are <= K
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int curAns = N + 1;
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if (__builtin_popcount(availMask) < K) {
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curAns = min(curAns, 1 + solve(bitMask | availMask));
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}
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// else if the number of available courses are greater than k, do this
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else {
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// generating the submasks of a given bitMask
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for (int subMask = availMask; subMask > 0; subMask = (subMask - 1) & availMask) {
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if (__builtin_popcount(subMask) == K) {
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curAns = min(curAns, 1 + solve(bitMask | subMask));
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}
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}
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}
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return dp[bitMask] = curAns;
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}
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int minNumberOfSemesters(int n, vector<vector<int>>& relations, int k) {
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N = n;
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K = k;
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graph.resize(N);
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for (auto &e : relations) {
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graph[--e[0]].push_back(--e[1]);
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}
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memset(dp, -1, sizeof(dp));
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finalBitMask = ((1 << N) - 1);
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return solve(0);
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}
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};

‎leetcode/1494/solution.cpp‎

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/*
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author: [email protected]
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time: O()
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space: O()
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Runtime: 149 ms, faster than 50.41% of C++ online submissions for Parallel Courses II.
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Memory Usage: 37.1 MB, less than 17.48% of C++ online submissions for Parallel Courses II.
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bfs
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*/
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#include <bits/stdc++.h>
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using namespace std;
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#define all(x) begin(x), end(x)
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typedef vector<int> vi;
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typedef vector<vector<int>> vvi;
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typedef int bint;
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class Solution {
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public:
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bint rel[16] = {};
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int required[16] = {};
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int fulfilled[16];
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int k;
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int n;
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int minNumberOfSemesters(int course_count, vector<vector<int>>& relations, int max_to_take) {
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k = max_to_take;
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n = course_count;
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/// n=2, toTakeNextTerm = 0x...110
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// can_take_first_term = (1<<(n+1)) - 2;
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for (auto & relation : relations){
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rel[relation[1]] |= 1<<relation[0];
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++required[relation[1]];
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// can_take_first_term &= ~1<<relation[1];
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}
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vi takens = {0};
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bfs(takens);
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return term_count;
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}
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int term_count = 0;
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int seen[65536] = {};
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void bfs(vi & takens){
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vi to_takes;
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for (auto & taken : takens){
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/// get course can be taken this term according to taken
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auto can_take_this_term = get_can_take_this_term(taken);
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if (can_take_this_term == 0){
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return;
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}
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/// select k courses from can_take_this_term
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auto selects_this_term = get_selects_this_term(can_take_this_term);
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for (auto & new_taken : selects_this_term){
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int to_take = taken | new_taken;
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if (!seen[to_take]){
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seen[to_take] = 1;
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to_takes.push_back(to_take);
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}
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}
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}
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++term_count;
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bfs(to_takes);
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}
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/// O(n2)
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inline int get_can_take_this_term(int & taken){
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memset(fulfilled+1, 0, 4*n);
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bint can_take_this_term = 0;
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/// O(n2)
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for (int j = 1; j<=n; ++j){
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// bint fulfilled_j = rel[j] & taken;
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// while (fulfilled_j!=0){
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// if (fulfilled_j & 1) ++fulfilled[j];
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// fulfilled_j >>= 1;
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// }
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fulfilled[j] = __builtin_popcount(rel[j] & taken);
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}
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for (int i=1; i<=n; ++i){
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if (fulfilled[i] >= required[i]){
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can_take_this_term |= 1<<i;
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}
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}
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can_take_this_term &= ~taken;
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return can_take_this_term;
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}
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inline vi get_selects_this_term(int & can_take_this_term){
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// int cnt_can_take_this_term = 0;
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// int tmp = can_take_this_term;
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// while (tmp!=0){
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// if (tmp & 1) ++cnt_can_take_this_term;
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// tmp >>= 1;
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// }
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// if (cnt_can_take_this_term<=k) return {can_take_this_term};
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if (__builtin_popcount(can_take_this_term)<=k) return {can_take_this_term};
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vi pos_1;
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pos_1.reserve(n);
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for (int i=0; can_take_this_term!=0; ++i){
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if (can_take_this_term & 1) pos_1.push_back(i);
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can_take_this_term >>= 1;
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}
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int N = pos_1.size();
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string bitmask(k, 1);
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bitmask.resize(N, 0);
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vi res;
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do {
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int select = 0;
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for (int i = 0; i < N; ++i) // [0..N-1] integers
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{
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if (bitmask[i]) {
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select |= 1<<pos_1[i];
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}
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}
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res.push_back(select);
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} while (std::prev_permutation(bitmask.begin(), bitmask.end()));
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return res;
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}
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};
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const static auto initialize = [] {
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std::ios::sync_with_stdio(false);
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std::cin.tie(nullptr);
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std::cout.tie(nullptr);
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return nullptr;
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}();

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