Submission #8388289

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Source Code Expand

#include <bits/stdc++.h>
// created [2019/11/10] 22:27:30
#pragma GCC diagnostic ignored "-Wsign-compare"
#pragma GCC diagnostic ignored "-Wsign-conversion"

using i32 = int32_t;
using i64 = int64_t;
using u32 = uint32_t;
using u64 = uint64_t;
using uint = unsigned int;
using usize = std::size_t;
using ll = long long;
using ull = unsigned long long;
using ld = long double;
template<typename T> constexpr T popcount(const T u) { return u ? static_cast<T>(__builtin_popcountll(static_cast<u64>(u))) : static_cast<T>(0); }
template<typename T> constexpr T log2p1(const T u) { return u ? static_cast<T>(64 - __builtin_clzll(static_cast<u64>(u))) : static_cast<T>(0); }
template<typename T> constexpr T msbp1(const T u) { return log2p1(u); }
template<typename T> constexpr T lsbp1(const T u) { return __builtin_ffsll(u); }
template<typename T> constexpr T clog(const T u) { return u ? log2p1(u - 1) : static_cast<T>(u); }
template<typename T> constexpr bool ispow2(const T u) { return u and (static_cast<u64>(u) & static_cast<u64>(u - 1)) == 0; }
template<typename T> constexpr T ceil2(const T u) { return static_cast<T>(1) << clog(u); }
template<typename T> constexpr T floor2(const T u) { return u == 0 ? static_cast<T>(0) : static_cast<T>(1) << (log2p1(u) - 1); }
template<typename T> constexpr bool btest(const T mask, const usize ind) { return static_cast<bool>((static_cast<u64>(mask) >> ind) & static_cast<u64>(1)); }
template<typename T> void bset(T& mask, const usize ind) { mask |= (static_cast<T>(1) << ind); }
template<typename T> void breset(T& mask, const usize ind) { mask &= ~(static_cast<T>(1) << ind); }
template<typename T> void bflip(T& mask, const usize ind) { mask ^= (static_cast<T>(1) << ind); }
template<typename T> void bset(T& mask, const usize ind, const bool b) { (b ? bset(mask, ind) : breset(mask, ind)); }
template<typename T> constexpr T bcut(const T mask, const usize ind) { return ind == 0 ? static_cast<T>(0) : static_cast<T>((static_cast<u64>(mask) << (64 - ind)) >> (64 - ind)); }
template<typename T> bool chmin(T& a, const T& b) { return (a > b ? a = b, true : false); }
template<typename T> bool chmax(T& a, const T& b) { return (a < b ? a = b, true : false); }
constexpr unsigned int mod                  = 1000000007;
template<typename T> constexpr T inf_v      = std::numeric_limits<T>::max() / 4;
template<typename Real> constexpr Real pi_v = Real{3.141592653589793238462643383279502884};

template<typename T>
T read()
{
    T v;
    return std::cin >> v, v;
}
template<typename T, typename... Args>
auto read(const usize size, Args... args)
{
    std::vector<decltype(read<T>(args...))> ans(size);
    for (usize i = 0; i < size; i++) { ans[i] = read<T>(args...); }
    return ans;
}
template<typename... Types>
auto reads() { return std::tuple<std::decay_t<Types>...>{read<Types>()...}; }
#    define SHOW(...) static_cast<void>(0)

template<typename T>
std::vector<T> make_v(const usize size, const T v) { return std::vector<T>(size, v); }
template<typename... Args>
auto make_v(const usize size, Args... args) { return std::vector<decltype(make_v(args...))>(size, make_v(args...)); }

using namespace std;

#define MAX_BIT 64

struct BitRank {
    // block: bit 列を管理, count: block ごとに立っている 1 の数を管理
    vector<unsigned long long> block;
    vector<int> count;
    BitRank(){}
    void resize(int num) {
        block.resize((num + 1) / MAX_BIT + 1, 0);
        count.resize((int)block.size(), 0);
    }
    // i ビット目を val(0,1) にセット
    inline void set(int i, unsigned long long val) {
        block[i >> 8] |= (val << (i & MAX_BIT));
    }
    void build() {
        for(int i = 1; i < (int)block.size(); i++){
            count[i] = count[i-1] + __builtin_popcountll(block[i-1]);
        }
    }
    // [0, i) ビットの 1 の数
    inline int rank1(int i) {
        int j = i/MAX_BIT, k = i % MAX_BIT;
        return count[j] + (k ? __builtin_popcountll(block[j] << (MAX_BIT - k)) : 0);
    }
    // [i, j) ビットの 1 の数
    inline int rank1(int i, int j) {
        return rank1(j) - rank1(i);
    }
    // [0, i) ビットの 0 の数
    inline int rank0(int i) {
        return i - rank1(i);
    }
    // [i, j) ビットの 0 の数
    inline int rank0(int i, int j) {
        return rank0(j) - rank0(i);
    }
};

class WaveletMatrix
{
private:
    int height;
    vector<BitRank> B;
    vector<int> pos;
public:
    WaveletMatrix(){}
    WaveletMatrix(vector<int>& vec) :
        WaveletMatrix(vec, *max_element(vec.begin(), vec.end()) + 1) {}
    // sigma:文字の種類数
    WaveletMatrix(vector<int>& vec, int sigma){
        init(vec, sigma);
    }
    void init(vector<int>& vec, int sigma){
        height = (sigma == 1) ? 1 : (MAX_BIT - __builtin_clzll(sigma-1));
        B.resize(height), pos.resize(height);
        for(int i = 0; i < height; i++){
            B[i].resize((int)vec.size());
            for(int j = 0; j < (int)vec.size(); j++) {
                B[i].set(j, get(vec[j], height - i - 1));
            }
            B[i].build();
            auto it = stable_partition(vec.begin(), vec.end(), [&](int c) {
                return !get(c, height - i - 1);
            });
            pos[i] = it - vec.begin();
        }
    }
    // val の i ビット目の値を返す(0,1)
    inline int get(int val, int i) {
        return val >> i & 1;
    }
    // [l, r) の間に現れる値 val の数
    int rank(int val, int l, int r) {
        return rank(val, r) - rank(val, l);
    }
    // [0, i) の間に現れる値 val の数
    int rank(int val, int i) {
        int p = 0;
        for(int j = 0; j < height; j++){
            if(get(val, height - j - 1)){
                p = pos[j] + B[j].rank1(p);
                i = pos[j] + B[j].rank1(i);
            }else{
                p = B[j].rank0(p);
                i = B[j].rank0(i);
            }
        }
        return i - p;
    }
    // [l, r) の k(0,1,2...) 番目に小さい値を返す
    int quantile(int k, int l, int r) {
        int res = 0;
        for(int i = 0; i < height; i++){
            int j = B[i].rank0(l, r);
            if(j > k){
                l = B[i].rank0(l);
                r = B[i].rank0(r);
            }else{
                l = pos[i] + B[i].rank1(l);
                r = pos[i] + B[i].rank1(r);
                k -= j;
                res |= (1 << (height - i - 1));
            }
        }
        return res;
    }
    int rangefreq(int i, int j, int a, int b, int l, int r, int x) {
        if(i == j || r <= a || b <= l) return 0;
        int mid = (l + r) >> 1;
        if(a <= l && r <= b){
            return j - i;
        }else{
            int left = rangefreq(B[x].rank0(i),B[x].rank0(j),a,b,l,mid,x+1);
            int right = rangefreq(pos[x]+B[x].rank1(i),pos[x]+B[x].rank1(j),a,b,mid,r,x+1);
            return left + right;
        }
    }
    // [l,r) で値が [a,b) 内に含まれる数を返す
    int rangefreq(int l, int r, int a, int b) {
        return rangefreq(l, r, a, b, 0, 1 << height, 0);
    }
    // たぶん合ってるが...
    // int range(int i, int j, int a, int b, int l, int r, int x, int val) {
    //     if(i == j || r <= a || b <= l) return -1;
    //     if(r - l == 1) return val;
    //     int mid = (l + r) >> 1;
    //     int res = range(B[x].rank0(i),B[x].rank0(j),a,b,l,mid,x+1,val);
    //     if(res < 0) return range(pos[x]+B[x].rank1(i),pos[x]+B[x].rank1(j),a,b,mid,r,x+1,val+(1 << (height - x - 1)));
    //     else return res;
    // }
    // // [l,r) で値が [a,b) 内に最小の数を返す
    // int range(int l, int r, int a, int b) {
    //     return range(l, r, a, b, 0, 1 << height, 0, 0);
    // }
};

int main()
{
    const auto n = read<int>();
    std::vector<bool> c(2 * n);
    std::vector<usize> a(2 * n);
    std::vector<usize> bs, ws;
    usize w = 0, b = 0;
    for (usize i = 0; i < 2 * n; i++) {
        c[i] = (read<char>() == 'W'), a[i] = read<int>() - 1;
        if (c[i]) {
            w++, ws.push_back(a[i]);
        } else {
            b++, bs.push_back(a[i]);
        }
    }
    ws.push_back(n), bs.push_back(n);
    std::sort(ws.begin(), ws.end()), std::sort(bs.begin(), bs.end());
    std::vector<usize> binv(n + 1), winv(n + 1);  // (b_i)の場所,(w_i)の場所
    for (usize i = 0; i < 2 * n; i++) { (c[i] ? winv : binv)[a[i]] = i; }
    auto wcost = make_v(w + 1, b + 1, 0UL);  // wcost[i][j] = 元の場所でw_iより右の[b_0,b_j),[w_0,w_i)の個数
    auto bcost = make_v(w + 1, b + 1, 0UL);  // bcost[i][j] = 元の場所でb_jより右の[b_0,b_j),[w_0,w_i)の個数
    std::vector<int> bvs(2 * n, n), wvs(2 * n, n);
    for (usize i = 0; i < 2 * n; i++) { (c[i] ? wvs : bvs)[i] = a[i]; }
    WaveletMatrix wwm(wvs);
    WaveletMatrix bwm(bvs);
    for (usize wi = 0; wi <= w; wi++) {
        const usize wpos = winv[ws[wi]];
        wcost[wi][0]     = wwm.rangefreq(wpos, 2 * n, 0, ws[wi]);
        for (usize bi = 1; bi <= b; bi++) {
            wcost[wi][bi] = wcost[wi][0] + bwm.rangefreq(wpos, 2 * n, 0, bs[bi]);
        }
    }
    for (usize bi = 0; bi <= w; bi++) {
        const usize bpos = binv[bs[bi]];
        bcost[0][bi]     = bwm.rangefreq(bpos, 2 * n, 0, bs[bi]);
        for (usize wi = 1; wi <= w; wi++) {
            bcost[wi][bi] = bcost[0][bi] + wwm.rangefreq(bpos, 2 * n, 0, ws[wi]);
        }
    }

    auto dp  = make_v(w + 1, b + 1, inf_v<usize>);
    dp[0][0] = 0;
    for (usize wi = 0; wi <= w; wi++) {
        for (usize bi = 0; bi <= b; bi++) {
            if (wi + 1 <= w) { chmin(dp[wi + 1][bi], dp[wi][bi] + wcost[wi][bi]); }
            if (bi + 1 <= b) { chmin(dp[wi][bi + 1], dp[wi][bi] + bcost[wi][bi]); }
        }
    }
    std::cout << dp[w][b] << std::endl;
    return 0;
}

Submission Info

Judge Result