NTHUGE - Cái túi 3

Tác giả: hieult

Ngôn ngữ: C++

#include <set>
#include <map>
#include <list>
#include <cmath>
#include <queue>
#include <stack>
#include <cstdio>
#include <string>
#include <vector>
#include <cstdlib>
#include <cstring>
#include <sstream>
#include <iomanip>
#include <iostream>
#include <algorithm>
#include <ctime>
#include <deque>
#include <bitset>
#include <cctype>
#include <utility>

using namespace std;

typedef long long ll;
typedef long double ld;
typedef unsigned int ui;
typedef unsigned long long ull;

#define Rep(i,n) for(int i = 0; i < (n); ++i)
#define Repd(i,n) for(int i = (n)-1; i >= 0; --i)
#define For(i,a,b) for(int i = (a); i <= (b); ++i)
#define Ford(i,a,b) for(int i = (a); i >= (b); --i)
#define Fit(i,v) for(__typeof((v).begin()) i = (v).begin(); i != (v).end(); ++i)
#define Fitd(i,v) for(__typeof((v).rbegin()) i = (v).rbegin(); i != (v).rend(); ++i)
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define sz(a) ((int)(a).size())
#define all(a) (a).begin(), (a).end()
#define ms(a,x) memset(a, x, sizeof(a))

template<class F, class T> T convert(F a, int p = -1) {
    stringstream ss;
    if (p >= 0)
        ss << fixed << setprecision(p);
    ss << a;
    T r;
    ss >> r;
    return r;
}
template<class T> T gcd(T a, T b) {
    T r;
    while (b != 0) {
        r = a % b;
        a = b;
        b = r;
    }
    return a;
}
template<class T> T lcm(T a, T b) {
    return a / gcd(a, b) * b;
}
template<class T> T sqr(T x) {
    return x * x;
}
template<class T> T cube(T x) {
    return x * x * x;
}
template<class T> int getbit(T s, int i) {
    return (s >> i) & 1;
}
template<class T> T onbit(T s, int i) {
    return s | (T(1) << i);
}
template<class T> T offbit(T s, int i) {
    return s & (~(T(1) << i));
}
template<class T> int cntbit(T s) {
    return s == 0 ? 0 : cntbit(s >> 1) + (s & 1);
}

const int bfsz = 1 << 16;
char bf[bfsz + 5];
int rsz = 0;
int ptr = 0;
char gc() {
    if (rsz <= 0) {
        ptr = 0;
        rsz = (int) fread(bf, 1, bfsz, stdin);
        if (rsz <= 0)
            return EOF;
    }
    --rsz;
    return bf[ptr++];
}
void ga(char &c) {
    c = EOF;
    while (!isalpha(c))
        c = gc();
}
int gs(char s[]) {
    int l = 0;
    char c = gc();
    while (isspace(c))
        c = gc();
    while (c != EOF && !isspace(c)) {
        s[l++] = c;
        c = gc();
    }
    s[l] = '\0';
    return l;
}
template<class T> bool gi(T &v) {
    v = 0;
    char c = gc();
    while (c != EOF && c != '-' && !isdigit(c))
        c = gc();
    if (c == EOF)
        return false;
    bool neg = c == '-';
    if (neg)
        c = gc();
    while (isdigit(c)) {
        v = v * 10 + c - '0';
        c = gc();
    }
    if (neg)
        v = -v;
    return true;
}

typedef pair<int, int> II;
const ld PI = acos(-1.0);
const ld eps = 1e-12;
const int dr[] = { -1, 0, +1, 0};
const int dc[] = { 0, +1, 0, -1};
const int inf = (int) 1e9 + 5;
const ll linf = (ll) 1e18 + 5;
const int mod = (ll) (1e9 + eps);

using namespace std;

int n, m;
ll L, R;
ll w[35], c[35];
vector<pair<ll, ll> > V1, V2;

int main(){
//	freopen("in.txt", "r", stdin);

	cin >> n >> L >> R;
	Rep(i, n) cin >> w[i] >> c[i];
	m = n / 2;
	n = n - n / 2;

	Rep(mask, (1 << n)){
		ll W = 0, C = 0;
		Rep(i, n) if(getbit(mask, i)){
			W += w[i];
			C += c[i];
		}
		V1.pb(mp(W, C));
	}

	Rep(mask, (1 << m)){
		ll W = 0, C = 0;
		Rep(i, m) if(getbit(mask, i)){
			W += w[i + n];
			C += c[i + n];
		}
		V2.pb(mp(W, C));
	}

	V1.pb(mp(linf, 0)); V2.pb(mp(linf, 0)); V2.pb(mp(-1, 0));

	sort(all(V1)); sort(all(V2));
	multiset<ll> S;
	multiset<ll>::iterator it;

//	Rep(i, sz(V1)) cout << V1[i].fi << " "; puts("");
//	Rep(i, sz(V2)) cout << V2[i].fi << " "; puts("");

	int u = 0, v = 0;
	while(u < sz(V2) - 1 && V2[u + 1].fi < L) u++;
	while(v < sz(V2) - 1 && V2[v + 1].fi <= R) v++;

	For(i, u + 1, v) S.insert(V2[i].se);

	ll res = 0;
	Rep(i, sz(V1)){
		if(V1[i].fi > R) break;
		while(u > 0 && V2[u].fi + V1[i].fi >= L) {
			S.insert(V2[u].se);
			u--;
		}
		while(v > 0 && V2[v].fi + V1[i].fi > R){
			S.erase(S.find(V2[v].se));
			v--;
		}
		if(!S.empty()){
			it = S.end(); it--;
			res = max(res, V1[i].se + (*it));
		}
	}

	cout << res;

	return 0;
}

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