动态规划之01背包

例题

OpenJudge - 采药

二维写法

#include <iostream>
using namespace std;
const int MAXN = 1010;
int f[MAXN][MAXN], w[MAXN], c[MAXN];
int main() {

    int t, m;
    cin >> t >> m;
    for(int i=1; i<=m; i++)
        cin >> w[i] >> c[i];

    for(int i=1; i<=m; i++)
        for(int j=1; j<=t; j++)
            if(w[i]<=j)
                f[i][j] = max(f[i-1][j], f[i-1][j-w[i]] + c[i]);
            else
                f[i][j] = f[i-1][j];

    cout << f[m][t] << endl;

    return 0;
}

维度压缩(一维)[tui]

#include <iostream>
using namespace std;
const int MAXN = 1010;
int f[MAXN], w[MAXN], c[MAXN];
int main() {
    int t, m;
    cin >> t >> m;
    for(int i=1; i<=m; i++)
        cin >> w[i] >> c[i];

    for(int i=1;i<=m;i++)
       for(int j=t;j>=w[i];j--)
             f[j]=max(f[j],f[j-w[i]]+c[i]);
    cout << f[t] << endl;

    return 0;
}