Submission #1230816

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Source Code Expand

/*
СТРОИМ СТЕНУ РАБОТЯГИ!
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*/
#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <cstdio>
#include <numeric>
#include <cstring>
#include <ctime>
#include <cstdlib>
#include <set>
#include <map>
#include <unordered_map>
#include <unordered_set>
#include <list>
#include <cmath>
#include <bitset>
#include <cassert>
#include <queue>
#include <stack>
#include <deque>
 
  
  
using namespace std;
  
  
template<typename T1, typename T2>inline void chkmin(T1 &x, T2 y) { if (x > y) x = y; }
template<typename T1, typename T2>inline void chkmax(T1 &x, T2 y) { if (x < y) x = y; }
/** Interface */
  
inline int readChar();
template <class T = int> inline T readInt(); 
template <class T> inline void writeInt( T x, char end = 0 );
inline void writeChar( int x ); 
inline void writeWord( const char *s );
  
/** Read */
  
static const int buf_size = 4096;
  
inline int getChar() {
    static char buf[buf_size];
    static int len = 0, pos = 0;
    if (pos == len) {
        pos = 0, len = fread(buf, 1, buf_size, stdin);
    }
    if (pos == len) {
        return -1;
    }
    return buf[pos++];
}
  
inline int readChar() {
    int c = getChar();
    while (c <= 32) {
        c = getChar();
    }
    return c;
}
  
template <class T>
inline T readInt() {
    int s = 1, c = readChar();
    T x = 0;
    if (c == '-')
        s = -1, c = getChar();
    while ('0' <= c && c <= '9')
        x = x * 10 + c - '0', c = getChar();
    return s == 1 ? x : -x;
}
  
/** Write */
  
static int write_pos = 0;
static char write_buf[buf_size];
  
inline void writeChar( int x ) {
    if (write_pos == buf_size)
        fwrite(write_buf, 1, buf_size, stdout), write_pos = 0;
    write_buf[write_pos++] = x;
}
  
template <class T> 
inline void writeInt( T x, char end ) {
    if (x < 0)
        writeChar('-'), x = -x;
  
    char s[24];
    int n = 0;
    while (x || !n)
        s[n++] = '0' + x % 10, x /= 10;
    while (n--)
        writeChar(s[n]);
    if (end)
        writeChar(end);
}
  
inline void writeWord( const char *s ) {     while (*s)
writeChar(*s++); }
  
struct Flusher {
    ~Flusher() {
        if (write_pos)
            fwrite(write_buf, 1, write_pos, stdout), write_pos = 0;
    }
} flusher;
  
using namespace std;


#define sz(c) (int)(c).size()
#define all(c) (c).begin(), (c).end()
#define rall(c) (c).rbegin(), (c).rend()
#define left left228
#define right right228
#define rank rank228
#define L(__) (__ << 1)
#define R(__) (L(__)|1) 
#define LL long long
#define oo (1<<30)
#define N 300005
int st1[N],top1,st2[N],top2;
int n,w,h,m,z[N],ans,A[4*N],add[4*N];


struct dot{
    int x,y;
    dot(int _x=0,int _y=0){ x=_x,y=_y;}
}a[N],b[N];


bool cmp(const dot &p,const dot &q){ return p.x<q.x||(p.x==q.x&&p.y<q.y);}


int find(int x) { 
    return lower_bound(z + 1, z + m + 1, x) - z;
}


void update(int t){ 
    A[t] = max(A[L(t)], A[R(t)]);
}


void build(int t, int l, int r) {
    int mid = (l + r) >> 1; 
    add[t] = 0;
    if (l == r) { 
        A[t] = -z[l]; 
        return;
    }
    build(L(t), l, mid);
    build(R(t), mid + 1, r);
    update(t);
}


void Add(int t, int d) { 
    add[t] += d;
    A[t] += d;
}


void push(int t) {
    if (add[t] == 0) {
        return;
    }
    Add(L(t), add[t]);
    Add(R(t), add[t]);
    add[t] = 0;
}


void modify(int t, int l, int r, int l1, int r1, int d) {
    int mid = (l + r) >> 1;
    if (l > r1 || r < l1 || l1 > r1) {
        return;
    }
    if (l >= l1 && r <= r1) {
        return Add(t, d);
    }
    push(t);
    modify(L(t), l, mid, l1, r1, d);
    modify(R(t), mid + 1, r, l1, r1, d);
    update(t);
}


void solve() {
    int mid = (h >> 1);
    for (int i = 1; i <= n; i++) {
        a[i] = b[i];
    }
    sort(a + 1,a + n + 1,cmp);
    if (a[n].x < w) {
        a[++n] = dot(w, 0);
    }
    top1 = top2 = 0;
    for (int i = 1; i <= n; i++) {
        z[i] = a[i].x;
    }
    m = n, z[++m] = 0, z[++m] = w;
    sort(z + 1, z + m + 1);
    m = unique(z + 1, z + m + 1) - z - 1;
    for (int i = 1; i <= n; i++) {
        a[i].x = find(a[i].x);
    }
    build(1, 1, m);
    if (a[1].x > 1) {
        modify(1, 1, m, 1, 1, h);
    }
    a[0].x = 1;
    for (int i = 1; i <= n; i++) {
        if (a[i].y <= mid) {
            modify(1, 1, m, a[i].x, a[i].x, h);
            chkmax(ans, A[1] + z[a[i].x]);
            modify(1, 1, m, a[st1[top1]].x, a[i].x - 1, -a[i].y);
            while (top1 && a[st1[top1]].y <= a[i].y) {
                modify(1, 1, m, a[st1[top1 - 1]].x, a[st1[top1]].x - 1, a[st1[top1]].y - a[i].y);
                top1--;
            }
            st1[++top1] = i;
        } else {
            modify(1, 1, m, a[i].x, a[i].x, h);
            chkmax(ans, A[1] + z[a[i].x]);
            modify(1, 1, m, a[st2[top2]].x,a[i].x - 1, a[i].y - h);
            while (top2 && a[st2[top2]].y >= a[i].y) {
                modify(1, 1, m, a[st2[top2 - 1]].x,a[st2[top2]].x - 1, a[i].y - a[st2[top2]].y);
                top2--;
            }
            st2[++top2] = i;
        }
    }
}


int main() {
    w = readInt(), h = readInt(), n = readInt();
    for (int i = 1; i <= n; i++) {
        b[i].x = readInt(), b[i].y = readInt();
    }
    solve();
    for (int i = 1; i <= n; i++) {
        swap(b[i].x, b[i].y);
    }
    swap(w, h);
    solve();
    cout << ans * 2LL << endl;
    return 0;
}

Submission Info

Judge Result