朴素做法(有一组数据TLE)
#include<iostream>
#include<algorithm>
using namespace std;
const int MAX = 1010;
int N, V;
int v[MAX], w[MAX];
int f[MAX][MAX];
int main()
{
cin >> N >> V;
for (int i = 1; i <= N; i ++) cin >> v[i] >> w[i];
for (int i = 1; i <= N; i ++) {
for (int j = 0; j <= V; j ++) {
for (int k = 0; j >= k * v[i]; k ++) {
f[i][j] = max(f[i][j], f[i - 1][j - k * v[i]] + k * w[i]);
}
}
}
cout << f[N][V];
return 0;
}
优化做法
#include<iostream>
#include<algorithm>
using namespace std;
const int MAX = 1010;
int N, V;
int v[MAX], w[MAX];
int f[MAX][MAX];
int main()
{
cin >> N >> V;
for (int i = 1; i <= N; i ++) cin >> v[i] >> w[i];
for (int i = 1; i <= N; i ++) {
for (int j = 0; j <= V; j ++) {
f[i][j] = f[i - 1][j];
if (j >= v[i]) f[i][j] = max(f[i][j], f[i][j - v[i]] + w[i]);
}
}
cout << f[N][V];
return 0;
}
再优化
#include<iostream>
#include<algorithm>
using namespace std;
const int MAX = 1010;
int N, V;
int v[MAX], w[MAX];
int f[MAX];
int main()
{
cin >> N >> V;
for (int i = 1; i <= N; i ++) cin >> v[i] >> w[i];
for (int i = 1; i <= N; i ++) {
for (int j = 0; j <= V; j ++) {
if (j >= v[i]) f[j] = max(f[j], f[j - v[i]] + w[i]);
}
}
cout << f[V];
return 0;
}