【BZOJ4587/BZOJ4408】【CC FRBSUM】【FJOI2016】神秘数/Forbidden Sum（主席树）

Description

https://www.lydsy.com/JudgeOnline/problem.php?id=4299

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Solution

考虑对于当前集合答案为$ans$，然后向集合加入一个$x$，如果$x\le ans$，那么答案变为$ans+x$，否则答案不变。
对于本题，如果当前答案为$ans$，那么查询小于等于$ans$的数的和是多少，如果大于等于$ans$，那么更新答案。
用主席树维护区间内小于等于$ans$的数的和即可。

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Code

/**************************************
 * Au: Hany01
 * Prob: Sep 24th, 2018
 * Date: [BZOJ4299][BZOJ4408][CC FRBSUM]

**************************************/

#include<bits/stdc++.h>

using namespace std;

typedef long long LL;
typedef long double LD;
typedef pair<int, int> PII;
typedef vector<int> VI;
#define File(a) freopen(a".in", "r", stdin), freopen(a".out", "w", stdout)
#define rep(i, j) for (register int i = 0, i##_end_ = j; i < i##_end_; ++ i)
#define For(i, j ,k) for (register int i = (j), i##_end_ = (k); i <= i##_end_; ++ i)
#define Fordown(i, j, k) for (register int i = (j), i##_end_ = (k); i >= i##_end_; -- i)
#define Set(a, b) memset(a, b, sizeof(a))
#define Cpy(a, b) memcpy(a, b, sizeof(a))
#define SZ(a) ((int)(a.size()))
#define ALL(a) a.begin(), a.end()
#define PB(a) push_back(a)
#define MP(a, b) make_pair(a, b)
#define x first
#define y second
#define INF (0x3f3f3f3f)
#define INF1 (2139062143)
#define y1 wozenmezhemecaia 
#ifdef hany01
#define debug(...) fprintf(stderr, __VA_ARGS__)
#else
#define debug(...)
#endif

template<typename T> inline bool chkmax(T &a, T b) { return a < b ? a = b, 1 : 0; }
template<typename T> inline bool chkmin(T &a, T b) { return b < a ? a = b, 1 : 0; }

inline int read() {
    register char c_; register int _, __;
    for (_ = 0, __ = 1, c_ = getchar(); !isdigit(c_); c_ = getchar()) if (c_ == '-')  __ = -1;
    for ( ; isdigit(c_); c_ = getchar()) _ = (_ << 1) + (_ << 3) + (c_ ^ 48);
    return _ * __;
}

const int maxn = 1e5 + 5, N = 1e9;

int n, tot, rt[maxn];

struct Node {
    int val, lc, rc;
}tr[maxn * 33];

#define mid ((l + r) >> 1)

void update(int las, int& t, int l, int r, int x) {
    tr[t = ++ tot] = tr[las], tr[t].val += x;
    if (l < r)
        if (x <= mid) update(tr[las].lc, tr[t].lc, l, mid, x);
        else update(tr[las].rc, tr[t].rc, mid + 1, r, x);
}

int query(int t1, int t2, int l, int r, int x, int y) {
    if (x <= l && r <= y) return tr[t2].val - tr[t1].val;
    if (y <= mid) return query(tr[t1].lc, tr[t2].lc, l, mid, x, y);
    if (x >  mid) return query(tr[t1].rc, tr[t2].rc, mid + 1, r, x, y);
    return query(tr[t1].lc, tr[t2].lc, l, mid, x, y) + query(tr[t1].rc, tr[t2].rc, mid + 1, r, x, y);
}

int main()
{
#ifdef hany01
    File("bzoj4299");
#endif

    For(i, 1, n = read()) update(rt[i - 1], rt[i], 1, N, read());
    for (register int m = read(), l, r, ans; m --; ) {
        l = read(), r = read(), ans = 0;
        while (chkmax(ans, query(rt[l - 1], rt[r], 1, N, 1, ans + 1)));
        printf("%d\n", ans + 1);
    }

    return 0;
}

/**************************************
 * Au: Hany01
 * Prob: Sep 24th, 2018
 * Date: [BZOJ4299][BZOJ4408][CC FRBSUM]
 * Email: [e-mail]
**************************************/

#include<bits/stdc++.h>

using namespace std;

typedef long long LL;
typedef long double LD;
typedef pair<int, int> PII;
typedef vector<int> VI;
#define File(a) freopen(a".in", "r", stdin), freopen(a".out", "w", stdout)
#define rep(i, j) for (register int i = 0, i##_end_ = j; i < i##_end_; ++ i)
#define For(i, j ,k) for (register int i = (j), i##_end_ = (k); i <= i##_end_; ++ i)
#define Fordown(i, j, k) for (register int i = (j), i##_end_ = (k); i >= i##_end_; -- i)
#define Set(a, b) memset(a, b, sizeof(a))
#define Cpy(a, b) memcpy(a, b, sizeof(a))
#define SZ(a) ((int)(a.size()))
#define ALL(a) a.begin(), a.end()
#define PB(a) push_back(a)
#define MP(a, b) make_pair(a, b)
#define x first
#define y second
#define INF (0x3f3f3f3f)
#define INF1 (2139062143)
#define y1 wozenmezhemecaia 
#ifdef hany01
#define debug(...) fprintf(stderr, __VA_ARGS__)
#else
#define debug(...)
#endif

template<typename T> inline bool chkmax(T &a, T b) { return a < b ? a = b, 1 : 0; }
template<typename T> inline bool chkmin(T &a, T b) { return b < a ? a = b, 1 : 0; }

inline int read() {
    register char c_; register int _, __;
    for (_ = 0, __ = 1, c_ = getchar(); !isdigit(c_); c_ = getchar()) if (c_ == '-')  __ = -1;
    for ( ; isdigit(c_); c_ = getchar()) _ = (_ << 1) + (_ << 3) + (c_ ^ 48);
    return _ * __;
}

const int maxn = 1e5 + 5, N = 1e9;

int n, tot, rt[maxn];

struct Node {
    int val, lc, rc;
}tr[maxn * 33];

#define mid ((l + r) >> 1)

void update(int las, int& t, int l, int r, int x) {
    tr[t = ++ tot] = tr[las], tr[t].val += x;
    if (l < r)
        if (x <= mid) update(tr[las].lc, tr[t].lc, l, mid, x);
        else update(tr[las].rc, tr[t].rc, mid + 1, r, x);
}

int query(int t1, int t2, int l, int r, int x, int y) {
    if (x <= l && r <= y) return tr[t2].val - tr[t1].val;
    if (y <= mid) return query(tr[t1].lc, tr[t2].lc, l, mid, x, y);
    if (x >  mid) return query(tr[t1].rc, tr[t2].rc, mid + 1, r, x, y);
    return query(tr[t1].lc, tr[t2].lc, l, mid, x, y) + query(tr[t1].rc, tr[t2].rc, mid + 1, r, x, y);
}

int main()
{
#ifdef hany01
    File("bzoj4299");
#endif

    For(i, 1, n = read()) update(rt[i - 1], rt[i], 1, N, read());
    for (register int m = read(), l, r, ans; m --; ) {
        l = read(), r = read(), ans = 0;
        while (chkmax(ans, query(rt[l - 1], rt[r], 1, N, 1, ans + 1)));
        printf("%d\n", ans + 1);
    }

    return 0;
}