26 lines
749 B
C++
26 lines
749 B
C++
|
#include <bits/stdc++.h>
|
||
|
|
|
||
|
|
using namespace std;
|
||
|
|
//完全背包的原始未优化版本
|
||
|
|
const int N = 1010;
|
||
|
|
int f[N][N];
|
||
|
|
int v[N], w[N];
|
||
|
|
|
||
|
|
int main() {
|
||
|
|
int n, m;
|
||
|
|
scanf("%d %d", &n, &m);
|
||
|
|
for (int i = 1; i <= n; i++) scanf("%d %d", &v[i], &w[i]);
|
||
|
|
|
||
|
|
//多层循环，万恶之源
|
||
|
|
//优化的策略是想办法干掉最里层的循环，就是经典的类比法对比公式，
|
||
|
|
//f[i][j-v] 去类比，用一个式子代替掉一层循环，使得时间复杂度降低
|
||
|
|
for (int i = 1; i <= n; i++)
|
||
|
|
for (int j = 0; j <= m; j++)
|
||
|
|
for (int k = 0; k * v[i] <= j; k++)
|
||
|
|
f[i][j] = max(f[i][j], f[i - 1][j - k * v[i]] + k * w[i]);
|
||
|
|
|
||
|
|
printf("%d\n", f[n][m]);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|