【DP】【01背包】【完全背包】Birthday 题解

#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
#include <set>
#include <queue>
#include <algorithm>
#include <vector>
#include <cstdlib>
#include <cmath>
#include <ctime>
#include <stack>
#define INF 2147483647
#define LL long long
#define clr(x) memset(x, 0, sizeof x)
#define digit (ch <  '0' || ch >  '9')

using namespace std;

template <class T> inline void read(T &x) {
int flag = 1; x = 0;
register char ch = getchar();
while( digit) { if(ch == '-')  flag = -1; ch = getchar(); }
while(!digit) { x = (x<<1)+(x<<3)+ch-'0'; ch = getchar(); }
x *= flag;
}

const int maxn = 2005;
const int maxm = 4005;
int n,m,c;
int w[maxn],a[maxn],b[maxn],dp[maxn];

int main() {
freopen("birthday.in","r",stdin);
freopen("birthday.out","w",stdout);
read(n); read(m);
for(register int i = 1; i <= n; i++) {
read(w[i]), read(a[i]), read(b[i]);
int flag = 0; a[i] += b[i];
for(register int j = m; j >= w[i]; j--) {
dp[j] = max(dp[j], dp[j-1]);
if(dp[j-w[i]]+a[i] > dp[j]) flag = 1, dp[j] = dp[j-w[i]]+a[i];
}
a[i] -= b[i];
if(flag == 1) for(register int j = w[i]; j <= m; j++) {
dp[j] = max(dp[j], dp[j-1]);
if(dp[j-w[i]]+a[i] > dp[j]) dp[j] = dp[j-w[i]]+a[i];
}
}
printf("%d",dp[m]);
return 0;
}