File size: 6,137 Bytes
14c9c2b | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 | #include <bits/stdc++.h>
using namespace std;
using ll = long long;
struct Item {
string name;
ll q, v, m, l;
};
ll parse_number(const string& s, size_t& pos) {
ll num = 0;
while (pos < s.size() && isdigit(static_cast<unsigned char>(s[pos]))) {
num = num * 10 + (s[pos] - '0');
++pos;
}
return num;
}
void expect_char(const string& s, size_t& pos, char expected) {
if (pos < s.size() && s[pos] == expected) {
++pos;
}
}
vector<Item> parse_json(const string& input_str) {
string json;
for (char c : input_str) {
if (!isspace(static_cast<unsigned char>(c))) {
json += c;
}
}
vector<Item> all_items;
size_t pos = 0;
if (pos < json.size() && json[pos] == '{') ++pos;
while (pos < json.size() && json[pos] != '}') {
if (pos < json.size() && json[pos] == '"') {
++pos;
size_t key_start = pos;
while (pos < json.size() && json[pos] != '"') ++pos;
string key(json.begin() + key_start, json.begin() + pos);
++pos; // "
expect_char(json, pos, ':');
expect_char(json, pos, '[');
Item it{key, 0, 0, 0, 0};
it.q = parse_number(json, pos);
expect_char(json, pos, ',');
it.v = parse_number(json, pos);
expect_char(json, pos, ',');
it.m = parse_number(json, pos);
expect_char(json, pos, ',');
it.l = parse_number(json, pos);
expect_char(json, pos, ']');
all_items.push_back(it);
if (pos < json.size() && json[pos] == ',') ++pos;
} else {
++pos; // skip unexpected
}
}
return all_items;
}
const ll MAX_MASS = 20000000LL;
const ll MAX_VOL = 25000000LL;
void try_greedy(const vector<Item>& items, const vector<int>& order, vector<ll>& best_counts, ll& best_value) {
vector<ll> this_counts(12, 0);
ll rem_m = MAX_MASS;
ll rem_v = MAX_VOL;
ll val = 0;
for (int o : order) {
int i = o;
ll tm = items[i].m;
ll tl = items[i].l;
ll tq = items[i].q;
if (tm == 0 || tl == 0) continue;
ll mx = min(tq, min(rem_m / tm, rem_v / tl));
this_counts[i] = mx;
val += mx * items[i].v;
rem_m -= mx * tm;
rem_v -= mx * tl;
}
if (val > best_value) {
best_value = val;
best_counts = this_counts;
}
}
ll best_value;
vector<ll> best_counts;
vector<Item> all_items;
vector<int> branch_order;
void recursion(int bidx, ll cur_mass, ll cur_vol, ll cur_val, vector<ll>& counts) {
if (bidx == 12) {
if (cur_val > best_value) {
best_value = cur_val;
best_counts = counts;
}
return;
}
int i = branch_order[bidx];
ll rem_m = MAX_MASS - cur_mass;
ll rem_v = MAX_VOL - cur_vol;
if (rem_m < 0 || rem_v < 0) return;
// upper bound including current and later
ll upper = cur_val;
for (int k = bidx; k < 12; ++k) {
int j = branch_order[k];
ll tm = all_items[j].m;
ll tl = all_items[j].l;
ll tq = all_items[j].q;
if (tm == 0 || tl == 0) continue;
ll mx = min(tq, min(rem_m / tm, rem_v / tl));
upper += mx * all_items[j].v;
}
if (upper <= best_value) return;
ll this_m = all_items[i].m;
ll this_l = all_items[i].l;
ll this_v = all_items[i].v;
ll this_q = all_items[i].q;
ll maxx = 0;
if (this_m > 0 && this_l > 0) {
maxx = min(this_q, min(rem_m / this_m, rem_v / this_l));
}
for (ll x = maxx; x >= 0; --x) {
ll new_mass = cur_mass + x * this_m;
ll new_vol = cur_vol + x * this_l;
if (new_mass > MAX_MASS || new_vol > MAX_VOL) continue;
// tighter upper for this x
ll upper_rem = 0;
ll nr_m = MAX_MASS - new_mass;
ll nr_v = MAX_VOL - new_vol;
for (int k = bidx + 1; k < 12; ++k) {
int j = branch_order[k];
ll tm = all_items[j].m;
ll tl = all_items[j].l;
ll tq = all_items[j].q;
if (tm == 0 || tl == 0) continue;
ll mx = min(tq, min(nr_m / tm, nr_v / tl));
upper_rem += mx * all_items[j].v;
}
if (cur_val + x * this_v + upper_rem > best_value) {
counts[i] = x;
recursion(bidx + 1, new_mass, new_vol, cur_val + x * this_v, counts);
}
}
counts[i] = 0;
}
int main() {
string input_str((istreambuf_iterator<char>(cin)), istreambuf_iterator<char>());
all_items = parse_json(input_str);
if (all_items.size() != 12) {
// error, but assume correct
return 1;
}
vector<ll> counts(12, 0);
best_value = 0;
best_counts = counts;
vector<int> order(12);
// first greedy v/m
iota(order.begin(), order.end(), 0);
sort(order.begin(), order.end(), [](int a, int b) {
return (__int128)all_items[a].v * all_items[b].m > (__int128)all_items[b].v * all_items[a].m;
});
branch_order = order; // use this for branching
try_greedy(all_items, order, best_counts, best_value);
// second greedy v/l
iota(order.begin(), order.end(), 0);
sort(order.begin(), order.end(), [](int a, int b) {
return (__int128)all_items[a].v * all_items[b].l > (__int128)all_items[b].v * all_items[a].l;
});
try_greedy(all_items, order, best_counts, best_value);
// third greedy v/(m+l)
iota(order.begin(), order.end(), 0);
sort(order.begin(), order.end(), [](int a, int b) {
ll am = all_items[a].m + all_items[a].l;
ll bm = all_items[b].m + all_items[b].l;
return (__int128)all_items[a].v * bm > (__int128)all_items[b].v * am;
});
try_greedy(all_items, order, best_counts, best_value);
// now search
recursion(0, 0LL, 0LL, 0LL, counts);
// output
cout << "{" << endl;
for (int i = 0; i < 12; ++i) {
if (i > 0) cout << "," << endl;
cout << " \"" << all_items[i].name << "\": " << best_counts[i];
}
cout << endl << "}" << endl;
return 0;
} |