題意:儲存空間爲N,有T首個,要求儘可能的填滿儲存空間,輸出存放的歌曲和總的佔用空間。
分析:01揹包,打印路徑。
#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;
const int MAX_N = 100000, MAX_M = 21, INF = 0x3f3f3f3f;
int N, T;
int a[MAX_M];
int d[MAX_N];
int path[MAX_M][MAX_N];
void print(int i, int j)
{
if(i < 0) return;
if(j>=0 && path[i+1][j] == 1)
{
print(i-1, j-a[i]);
printf("%d ", a[i]);
}
else
print(i-1, j);
}
void solve()
{
memset(d, 0, sizeof(d));
memset(path, 0, sizeof(path));
for(int i = 0; i < T; i++)
for(int j = N; j >= a[i]; j--)
if(d[j] < d[j-a[i]] + a[i])
{
d[j] = d[j-a[i]] + a[i];
path[i+1][j] = 1;
}
print(T-1, N);
printf("sum:%d\n", d[N]);
}
int main()
{
//freopen("in.txt", "r", stdin);
while(scanf("%d%d", &N, &T) !=EOF)
{
for(int i = 0; i < T; i++)
scanf("%d", a+i);
solve();
}
return 0;
}