Luogu3594 [POI2015]WIL-Wilcze doły （双端队列）

单调性显然，双端队列队列维护严格单调递减手写双端队列真的可恶。

#include <iostream>

#include <cstdio>

#include <cstring>

#include <algorithm>

#include <cmath>

#define R(a,b,c) for(register int  a = (b); a <= (c); ++ a)

#define nR(a,b,c) for(register int  a = (b); a >= (c); -- a)

#define Max(a,b) ((a) > (b) ? (a) : (b))

#define Min(a,b) ((a) < (b) ? (a) : (b))

#define Fill(a,b) memset(a, b, sizeof(a))

#define Abs(a) ((a) < 0 ? -(a) : (a))

#define Swap(a,b) a^=b^=a^=b

#define ll long long

#define ON_DEBUG

#ifdef ON_DEBUG

#define D_e_Line printf("\n\n----------\n\n")

#define D_e(x)  cout << #x << " = " << x << endl

#define Pause() system("pause")

#define FileOpen() freopen("in.txt","r",stdin);

#else

#define D_e_Line ;

#define D_e(x)  ;

#define Pause() ;

#define FileOpen() ;

#endif

struct ios{

    template<typename ATP>ios& operator >> (ATP &x){

        x = 0; int f = 1; char c;

        for(c = getchar(); c < '0' || c > '9'; c = getchar()) if(c == '-')  f = -1;

        while(c >= '0' && c <= '9') x = x * 10 + (c ^ '0'), c = getchar();

        x*= f;

        return *this;

    }

}io;

using namespace std;

//#include <queue>

const int N = 2000007;

int a[N];

long long sum[N], x[N];

//deque<int> q;

int q[N], t, h = 1;

int main(){

//FileOpen();

	int n, d;

	long long Val;

	io >> n >> Val >> d;

    R(i,1,n){

    	io >> a[i];

    	sum[i] = sum[i - 1] + a[i];

    }

   	R(i,d,n){

   		x[i] = sum[i] - sum[i - d];

   	}

	int ans = d;

	q[++t] = d;

	int l = 1;

	R(r,d,n){

		while(h <= t && x[r] >= x[q[t]]) --t;

		q[++t] = r;

		while(h <= t && q[h] - d + 1< l) ++h;

		while(h <= t && sum[r] - sum[l - 1] - x[q[h]] > Val){

			++l;

			while(h <= t && q[h] - d + 1 < l) ++h;

		}

		ans = Max(ans, r - l + 1);

	}

    printf("%d", ans);

    return 0;

}

Luogu3594 [POI2015]WIL-Wilcze doły （双端队列）的相关教程结束。