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read chokudai book with C++
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| #include <bits/stdc++.h> | |
| using namespace std; | |
| // | |
| // P. 177 knapsack | |
| // g++ -O3 knapsack2.cpp -std=gnu++1y && ./a.out | |
| // | |
| int knapsack2(int n, int w){ | |
| int ws[5] = {3,4,1,2,3}; | |
| int ps[5] = {2,3,2,3,6}; | |
| int maxw = 10; | |
| if (w > maxw) return -1; | |
| if (n >= 5) return 0; | |
| return max( knapsack2(n+1, w), | |
| knapsack2(n+1, w+ws[n]) + ps[n]); | |
| } | |
| int knapsack_dp(){ | |
| int ws[5] = {3,4,1,2,3}; | |
| int ps[5] = {2,3,2,3,6}; | |
| int dp[6][11] = {0}; | |
| int maxw = 10; | |
| int ret = 0; | |
| for(int i = 0; i < 5; ++i) | |
| { | |
| for(int j = 0; j < maxw; ++j) | |
| { | |
| if(j+ws[i] <= maxw) | |
| { | |
| //cout << i << ':' << j << " :: " << dp[i+1][j+ws[i]] << '/' << dp[i][j] + ps[i] << endl; | |
| dp[i+1][j+ws[i]] = max( dp[i+1][ j+ws[i] ], dp[i][j] + ps[i]); | |
| ret = max(dp[i+1][j+ws[i]], ret); | |
| } | |
| } | |
| } | |
| return ret; | |
| } | |
| int knapsack_dp_cpp14(){ | |
| array<int,5> ws{3,4,1,2,3}; | |
| array<int,5> ps{2,3,2,3,6}; | |
| array<array<int, 6>, 11> dp{}; | |
| const int maxw = 10; | |
| int ret = 0; | |
| for(int i = 0; i < 5; ++i){ | |
| for(int j = 0; j <= maxw; ++j){ | |
| if(j+ws[i] <= maxw) | |
| { | |
| //cout << i << ':' << j << " :: " << dp[i+1][j+ws[i]] << '/' << dp[i][j] + ps[i] << endl; | |
| //dp[i+1][j+ws[i]] = max(dp[i+1][j+ws[i]], dp[i][j] + ps.at(i)); | |
| dp[i+1][j+ws[i]] = max(dp[i+1][j+ws[i]], dp[i][j] + ps[i]); | |
| ret = max(dp[i+1][j+ws[i]], ret); | |
| } | |
| } | |
| } | |
| return ret; | |
| } | |
| int main(){ | |
| cout << "knapsack" << endl; | |
| cout << knapsack2(0, 0) << endl; //=> 15 | |
| cout << knapsack_dp() << endl; //=> 14 | |
| cout << knapsack_dp_cpp14() << endl; //=> 14 | |
| return 0; | |
| } |
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