Knapsack Problem | Aizu Online Judge http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=DPL_1_C&lang=jp

DPL_1_C.cpp

#include <iostream>
#include <algorithm>

using namespace std;

int main(){
  int dp[101][10001];
  int value[101], weight[101];
  int n, w;
  cin >> n >> w;
  for (int i = 0; i < n; i++)
    cin >> value[i] >> weight[i];
  for (int i = 0; i <= w; i++)
    dp[0][i] = 0;
  for (int i = 0; i < n; i++) {
    for (int j = 0; j <= w; j++) {
      if (j >= weight[i]) {
        // int t = j/weight[i]; // ついついこんな風に考えてしまいます…。
        // dp[i+1][j] = max(dp[i][j-t*weight[i]]+t*value[i], dp[i][j]);
        dp[i+1][j] = max(max(dp[i][j-weight[i]]+value[i], dp[i+1][j-weight[i]]+value[i]),
                         dp[i][j]);
      }
      else {
        dp[i+1][j] = dp[i][j];
      }
    }
  }
  cout << dp[n][w] << endl;
  return 0;
}