57 lines
1.4 KiB
C++
57 lines
1.4 KiB
C++
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/**
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* File: fractional_knapsack.cpp
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* Created Time: 2023-07-20
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* Author: krahets (krahets@163.com)
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*/
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#include "../utils/common.hpp"
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/* <20><>Ʒ */
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class Item {
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public:
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int w; // <20><>Ʒ<EFBFBD><C6B7><EFBFBD><EFBFBD>
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int v; // <20><>Ʒ<EFBFBD><C6B7>ֵ
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Item(int w, int v) : w(w), v(v) {
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}
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};
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/* <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>̰<EFBFBD><CCB0> */
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double fractionalKnapsack(vector<int> &wgt, vector<int> &val, int cap) {
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// <20><><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ʒ<EFBFBD>б<EFBFBD><D0B1><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ԣ<EFBFBD><D4A3><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ֵ
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vector<Item> items;
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for (int i = 0; i < wgt.size(); i++) {
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items.push_back(Item(wgt[i], val[i]));
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}
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// <20><><EFBFBD>յ<EFBFBD>λ<EFBFBD><CEBB>ֵ item.v / item.w <20>Ӹߵ<D3B8><DFB5>ͽ<EFBFBD><CDBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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sort(items.begin(), items.end(), [](Item &a, Item &b) { return (double)a.v / a.w > (double)b.v / b.w; });
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// ѭ<><D1AD>̰<EFBFBD><CCB0>ѡ<EFBFBD><D1A1>
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double res = 0;
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for (auto &item : items) {
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if (item.w <= cap) {
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// <20><>ʣ<EFBFBD><CAA3><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>㣬<EFBFBD><EFBFBD>ǰ<EFBFBD><C7B0>Ʒ<EFBFBD><C6B7><EFBFBD><EFBFBD>װ<EFBFBD><D7B0><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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res += item.v;
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cap -= item.w;
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} else {
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// <20><>ʣ<EFBFBD><CAA3><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>㣬<EFBFBD><EFBFBD>ǰ<EFBFBD><C7B0>Ʒ<EFBFBD><C6B7>һ<EFBFBD><D2BB><EFBFBD><EFBFBD>װ<EFBFBD><D7B0><EFBFBD><EFBFBD><EFBFBD><EFBFBD>
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res += (double)item.v / item.w * cap;
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// <20><><EFBFBD><EFBFBD>ʣ<EFBFBD><CAA3><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>ѭ<EFBFBD><D1AD>
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break;
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}
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}
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return res;
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}
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/* Driver Code */
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int main() {
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vector<int> wgt = {10, 20, 30, 40, 50};
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vector<int> val = {50, 120, 150, 210, 240};
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int cap = 50;
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// ̰<><CCB0><EFBFBD>㷨
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double res = fractionalKnapsack(wgt, val, cap);
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cout << "<EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD><EFBFBD>Ʒ<EFBFBD><EFBFBD>ֵΪ " << res << endl;
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return 0;
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}
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