| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 1004711 | ProtonDecay314 | Robots (IOI13_robots) | C++17 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include<bits/stdc++.h>
// #define DEBUG
using namespace std;
typedef long long ll;
typedef vector<ll> vll;
typedef vector<int> vi;
vi to_vec(int arr[], int sz) {
vi res(sz, 0);
for(int i = 0; i < sz; i++) {
res[i] = arr[i];
}
return res;
}
struct toy {
int w;
int s;
int wi;
int si;
bool operator<(const toy& other) const {
return si < other.si;
}
};
int get_flimsiest_robot(const vi& robots, int val) {
int l = -1, r = robots.size();
while(r - l > 1) {
int m = (l + r) >> 1;
if(robots[m] > val) r = m;
else l = m;
}
return r;
}
bool poss(const vector<toy>& toys, int a, int b, int t, int d) {
// Check if possible for a certain max duration d
int cur_added = 0;
priority_queue<toy> q;
int p1 = 0, p2 = 0;
for(int i = 0; i < a; i++) {
#ifdef DEBUG
cout << "POINTERS: " << p1 << " " << p2 << endl;
#endif
// Move pointer 1 to the first toy whose wi equals i
while(p1 < t && toys[p1].wi < i) p1++; // ! oop, I did toys[p1].wi > i haha
p2 = p1;
while(p2 < t && toys[p2].wi <= i) p2++;
// Add these new toys to the priority queue
for(int j = p1; j < p2; j++) {
q.push(toys[j]);
}
// Assign "d" of these toys to the current weak robot wr[i]
// (i.e., pop d times from the priority queue)
for(int j = 0; j < d; j++) {
if(q.empty()) break;
#ifdef DEBUG
cout << q.top().si << endl;
#endif
q.pop();
}
}
// Push the toys that cannot be handled by any weak robot
// These can potentially be handled by small robots though
for(int i = p2; i < t; i++) {
q.push(toys[i]);
}
// Now, we've assigned some toys to the weak robots
// We now assign the rest to the small robots
#ifdef DEBUG
cout << "NUM TOYS TO SMALL: " << q.size() << endl;
#endif
if(q.empty()) return true;
int cur_ind = b - 1;
while(cur_ind >= 0) {
if(q.top().si > cur_ind) return false;
for(int i = 0; i < d; i++) {
if(q.empty()) return true;
q.pop();
}
if(q.empty()) return true;
cur_ind--;
}
return q.empty();
}
// IOI Function Signatures
int putaway(int a, int b, int t, int xarr[], int yarr[], int warr[], int sarr[]) {
// x is weight, y is size
vi x = to_vec(xarr, a), y = to_vec(yarr, b);
// Sorting robots
sort(x.begin(), x.end());
sort(y.begin(), y.end());
// Storing Toys
vector<toy> toys;
toys.reserve(t);
for(int i = 0; i < t; i++) {
toys.push_back({warr[i], sarr[i], 0, 0});
}
// Binary searching to get the index of the first robot that can handle this
for(int i = 0; i < t; i++) {
toys[i].wi = get_flimsiest_robot(x, toys[i].w);
toys[i].si = get_flimsiest_robot(x, toys[i].s);
// No robot can pick this up, return -1
if(toys[i].wi == a && toys[i].si == b) return -1;
}
// Sort the toys, first from lightest to heaviest, then largest to smallest
sort(toys.begin(), toys.end(), [](toy a, toy b) {
return a.wi < b.wi || (a.wi == b.wi && a.si > b.si);
});
int l = 0, r = t + 1;
while(r - l > 1) {
int m = (l + r) >> 1;
if(poss(toys, a, b, t, m)) r = m;
else l = m;
}
return r;
};
// Driver Function
int main() {
int a, b, t;
cin >> a >> b >> t;
vi x(a, 0);
vi y(b, 0);
for(int& v : x) {
cin >> v;
}
for(int& v : y) {
cin >> v;
}
vi w(t, 0);
vi s(t, 0);
for(int i = 0; i < t; i++) {
cin >> w[i] >> s[i];
}
cout << putaway(a, b, t, &x[0], &y[0], &w[0], &s[0]) << endl;
return 0;
}