UOJ#386. 【UNR #3】鸽子固定器(链表)

#include<cstdio>
#include<algorithm>
#include<queue>
#define Pair pair<int, int> 
#define MP(x, y) make_pair(x, y)
#define fi first
#define se second
#define LL long long
 #define int long long  
using namespace std;
const int MAXN = 2 * 1e5 + 10, B = 25000;
inline int read() {
    char c = getchar(); int x = 0, f = 1;
    while(c < '0' || c > '9') {if(c == '-') f = -1; c = getchar();}
    while(c >= '0' && c <= '9') x = x * 10 + c - '0', c = getchar();
    return x * f;
}
int N, M, ds, dv;
int l[MAXN], r[MAXN];
LL Get(LL x, int opt) {
    if(opt == 1) return x;
    else return x * x;
}
struct Node {
    int s, v;
    bool operator < (const Node &rhs) const {
        return s == rhs.s ? v < rhs.v : s < rhs.s;
    }
}a[MAXN];
main() {
    priority_queue<Pair> q;
    N = read(); M = read(); ds = read(); dv = read();
    for(int i = 1; i <= N; i++) {
        a[i].s = read(), a[i].v = read(); // 澶у皬 / 鐗㈠浐绋嬪害
        
    }
    sort(a + 1, a + N + 1);
    for(int i = 1; i <= N; i++) {
        q.push(MP(-a[i].v, i));
    }
    int ans = 0;
    for(int i = 1; i <= N; i++) {
        int sum = 0;
        for(int j = i; j <= i + M - 1 && j <= N; j++) {
            sum += a[j].v;
            ans = max(ans, Get(sum, dv) - Get(a[j].s - a[i].s, ds));
        }
    }
  // printf("%d\n", ans);
    for(int i = 1; i <= N; i++) r[i] = i + 1, l[i] = i - 1;
    while(!q.empty()) {
     //   printf("%d\n", q.top().fi);
        int pos = q.top().se; q.pop();
        int sum = a[pos].v, x = pos, y = pos;
        for(int j = 1; j < M; j++) {
            if(l[x]) x = l[x], sum += a[x].v;
            else if(r[y] <= N) y = r[y], sum += a[y].v;
        }
        while(x != r[pos] && y <= N) {
            ans = max(ans, Get(sum, dv) - Get(a[y].s - a[x].s, ds));
            sum -= a[x].v;
            x = r[x]; y = r[y];
            sum += a[y].v;
        }
        r[l[pos]] = r[pos];
        l[r[pos]] = l[pos];
    }
    printf("%lld", ans);
    
    return 0;
}
/*
*/