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  • CF1322D Reality Show [dp]

    题在这

    很显然的消消乐,我们看怎么做。

    显然的转移方程 (f_{p,j} = f_{p,j-1} + c_p - s_i) (p = l_i)

    然后的话考虑另外一种转移 (f_{j + 1, frac{k}{2}} = f_{j,k} + frac{k}{2} c_{j+1})

    你考虑到他要你求一个单调不升的序列,你没有办法保证 (forall jleq i , l_j leq l_i)

    那么反过来,求一个单调不降的序列,如果能更新,那么显然满足条件。

    // powered by c++11
    // by Isaunoya
    #include <bits/stdc++.h>
    
    #define rep(i, x, y) for (register int i = (x); i <= (y); ++i)
    #define Rep(i, x, y) for (register int i = (x); i >= (y); --i)
    
    using namespace std;
    using db = double;
    using ll = long long;
    using uint = unsigned int;
    using ull = unsigned long long;
    
    using pii = pair<int, int>;
    
    #define fir first
    #define sec second
    
    template <class T>
    
    void cmax(T& x, const T& y) {
      if (x < y) x = y;
    }
    
    template <class T>
    
    void cmin(T& x, const T& y) {
      if (x > y) x = y;
    }
    
    #define all(v) v.begin(), v.end()
    #define sz(v) ((int)v.size())
    #define pb emplace_back
    
    template <class T>
    
    void sort(vector<T>& v) {
      sort(all(v));
    }
    
    template <class T>
    
    void reverse(vector<T>& v) {
      reverse(all(v));
    }
    
    template <class T>
    
    void unique(vector<T>& v) {
      sort(all(v)), v.erase(unique(all(v)), v.end());
    }
    
    void reverse(string& s) { reverse(s.begin(), s.end()); }
    
    const int io_size = 1 << 23 | 233;
    const int io_limit = 1 << 22;
    struct io_in {
      char ch;
    #ifndef __WIN64
      char getchar() {
        static char buf[io_size], *p1 = buf, *p2 = buf;
    
        return (p1 == p2) && (p2 = (p1 = buf) + fread(buf, 1, io_size, stdin), p1 == p2) ? EOF : *p1++;
      }
    #endif
      io_in& operator>>(char& c) {
        for (c = getchar(); isspace(c); c = getchar())
          ;
    
        return *this;
      }
      io_in& operator>>(string& s) {
        for (s.clear(); isspace(ch = getchar());)
          ;
    
        if (!~ch) return *this;
    
        for (s = ch; !isspace(ch = getchar()) && ~ch; s += ch)
          ;
    
        return *this;
      }
    
      io_in& operator>>(char* str) {
        char* cur = str;
        while (*cur) *cur++ = 0;
    
        for (cur = str; isspace(ch = getchar());)
          ;
        if (!~ch) return *this;
    
        for (*cur = ch; !isspace(ch = getchar()) && ~ch; *++cur = ch)
          ;
    
        return *++cur = 0, *this;
      }
    
      template <class T>
    
      void read(T& x) {
        bool f = 0;
        while ((ch = getchar()) < 48 && ~ch) f ^= (ch == 45);
    
        x = ~ch ? (ch ^ 48) : 0;
        while ((ch = getchar()) > 47) x = x * 10 + (ch ^ 48);
        x = f ? -x : x;
      }
    
      io_in& operator>>(int& x) { return read(x), *this; }
    
      io_in& operator>>(ll& x) { return read(x), *this; }
    
      io_in& operator>>(uint& x) { return read(x), *this; }
    
      io_in& operator>>(ull& x) { return read(x), *this; }
    
      io_in& operator>>(db& x) {
        read(x);
        bool f = x < 0;
        x = f ? -x : x;
        if (ch ^ '.') return *this;
    
        double d = 0.1;
        while ((ch = getchar()) > 47) x += d * (ch ^ 48), d *= .1;
        return x = f ? -x : x, *this;
      }
    } in;
    
    struct io_out {
      char buf[io_size], *s = buf;
      int pw[233], st[233];
    
      io_out() {
        set(7);
        rep(i, pw[0] = 1, 9) pw[i] = pw[i - 1] * 10;
      }
    
      ~io_out() { flush(); }
    
      void io_chk() {
        if (s - buf > io_limit) flush();
      }
    
      void flush() { fwrite(buf, 1, s - buf, stdout), fflush(stdout), s = buf; }
    
      io_out& operator<<(char c) { return *s++ = c, *this; }
    
      io_out& operator<<(string str) {
        for (char c : str) *s++ = c;
        return io_chk(), *this;
      }
    
      io_out& operator<<(char* str) {
        char* cur = str;
        while (*cur) *s++ = *cur++;
        return io_chk(), *this;
      }
    
      template <class T>
    
      void write(T x) {
        if (x < 0) *s++ = '-', x = -x;
    
        do {
          st[++st[0]] = x % 10, x /= 10;
        } while (x);
    
        while (st[0]) *s++ = st[st[0]--] ^ 48;
      }
    
      io_out& operator<<(int x) { return write(x), io_chk(), *this; }
    
      io_out& operator<<(ll x) { return write(x), io_chk(), *this; }
    
      io_out& operator<<(uint x) { return write(x), io_chk(), *this; }
    
      io_out& operator<<(ull x) { return write(x), io_chk(), *this; }
    
      int len, lft, rig;
    
      void set(int _length) { len = _length; }
    
      io_out& operator<<(db x) {
        bool f = x < 0;
        x = f ? -x : x, lft = x, rig = 1. * (x - lft) * pw[len];
        return write(f ? -lft : lft), *s++ = '.', write(rig), io_chk(), *this;
      }
    } out;
    #define int long long
    
    template <int sz, int mod>
    
    struct math_t {
      math_t() {
        fac.resize(sz + 1), ifac.resize(sz + 1);
        rep(i, fac[0] = 1, sz) fac[i] = fac[i - 1] * i % mod;
    
        ifac[sz] = inv(fac[sz]);
        Rep(i, sz - 1, 0) ifac[i] = ifac[i + 1] * (i + 1) % mod;
      }
    
      vector<int> fac, ifac;
    
      int qpow(int x, int y) {
        int ans = 1;
        for (; y; y >>= 1, x = x * x % mod)
          if (y & 1) ans = ans * x % mod;
        return ans;
      }
    
      int inv(int x) { return qpow(x, mod - 2); }
    
      int C(int n, int m) {
        if (n < 0 || m < 0 || n < m) return 0;
        return fac[n] * ifac[m] % mod * ifac[n - m] % mod;
      }
    };
    
    int gcd(int x, int y) { return !y ? x : gcd(y, x % y); }
    int lcm(int x, int y) { return x * y / gcd(x, y); }
    
    int n, m;
    const int maxn = 1 << 12;
    const int inf = 1e18;
    int l[maxn], s[maxn], c[maxn];
    int t[maxn], f[maxn][maxn];
    
    signed main() {
      // code begin.
      in >> n >> m;
      t[0] = n, m += n;
      Rep(i, n, 1) in >> l[i];
      Rep(i, n, 1) in >> s[i];
      rep(i, 1, m) in >> c[i];
      rep(i, 0, m) rep(j, 1, n) f[i][j] = -inf;
      rep(i, 1, n) t[i] = t[i - 1] >> 1;
      rep(i, 1, n) {
        int p = l[i];
        Rep(j, n, 1) cmax(f[p][j], f[p][j - 1] + c[p] - s[i]);
        rep(j, p, m) rep(k, 0, t[j - p]) cmax(f[j + 1][k >> 1], f[j][k] + (k >> 1) * c[j + 1]);
      }
      out << f[m][0] << '
    ';
      return 0;
      // code end.
    }
    
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  • 原文地址:https://www.cnblogs.com/Isaunoya/p/12624174.html
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