【BZOJ1649】[Usaco2006 Dec]Cow Roller Coaster【揹包DP】

【題目鏈接】

設dp[i][j]，表示前i個位置，花費爲j，的最大有趣指數。

然後類似揹包一樣轉移。

/* Telekinetic Forest Guard */
#include <cstdio>
#include <cstring>
#include <algorithm>

using namespace std;

const int maxn = 1005, maxm = 10005;

int L, n, m, dp[maxn][maxn];

struct _data {
	int l, r, w, c;

	bool operator < (const _data &x) const {
		return l < x.l;
	}
} track[maxm];

inline int iread() {
	int f = 1, x = 0; char ch = getchar();
	for(; ch < '0' || ch > '9'; ch = getchar()) f = ch == '-' ? -1 : 1;
	for(; ch >= '0' && ch <= '9'; ch = getchar()) x = x * 10 + ch - '0';
	return f * x;
}

int main() {
	L = iread(); n = iread(); m = iread();
	for(int i = 1; i <= n; i++) track[i].l = iread(), track[i].r = track[i].l + iread(), track[i].w = iread(), track[i].c = iread();
	sort(track + 1, track + 1 + n);
	memset(dp, -1, sizeof(dp));
	dp[0][0] = 0;
	for(int i = 1; i <= n; i++)
		for(int j = track[i].c; j <= m; j++) if(~dp[track[i].l][j - track[i].c])
			dp[track[i].r][j] = max(dp[track[i].r][j], dp[track[i].l][j - track[i].c] + track[i].w);
	int ans = -1;
	for(int i = 1; i <= m; i++) ans = max(ans, dp[L][i]);
	printf("%d\n", ans);
	return 0;
}