去成都考试的题目的原题?
思路是一眼内容,就是代码不好写.
直接考虑用线段树维护一下区间草的信息即可…
c++代码如下:
/*
code by Tgotp
*/
#include<iostream>
#include<cctype>
#include<cstdio>
#include<string>
#include<cstring>
#include<algorithm>
#include<queue>
#include<vector>
#include<map>
#define lowbit(x) (x&-x)
#define eps 1e-8
#define rep(i,x,y) for(register int i = x ; i <= y; ++ i)
#define repd(i,x,y) for(register int i = x ; i >= y; -- i)
using namespace std;
typedef long long ll;
template<typename T>inline bool chkmax(T&x,T y) { return x < y ? x = y,1 : 0; }
template<typename T>inline bool chkmin(T&x,T y){ return x > y ? x = y,1 : 0; }
template<typename T>inline void read(T&x)
{
x = 0;char c;int sign = 1;
do { c = getchar(); if(c == '-') sign = -1; }while(!isdigit(c));
do { x = x * 10 + c - '0'; c = getchar(); }while(isdigit(c));
x *= sign;
}
inline void init(string name)
{
string in = name + ".in",out = name + ".out";
freopen(in.c_str(),"r",stdin);
freopen(out.c_str(),"w",stdout);
}
const int N = 5e5+7,inf = 1e9+7;
int a[N],n,m;
struct segment_Tree
{
ll lzy1[N<<2],lzy2[N<<2],sum[N<<2],tot[N<<2];
ll mi1[N<<2],mx1[N<<2];
ll mx2[N<<2],mi2[N<<2];
void build(int id,int l,int r)
{
lzy1[id] = -1;
if(l == r)
{
mi1[id] = mx1[id] = a[l];
tot[id] = a[l];
return;
}
int mid = l + r >> 1;
build(id<<1,l,mid); build(id<<1|1,mid + 1,r);
mi1[id] = min(mi1[id<<1],mi1[id<<1|1]);
mx1[id] = max(mx1[id<<1],mx1[id<<1|1]);
tot[id] = tot[id<<1] + tot[id<<1|1];
}
inline void put_down(int id,int l,int r)
{
if(l > r) return;
if(~lzy1[id])
{
if(l != r) lzy1[id << 1] = lzy1[id<<1|1] = lzy1[id];
mx2[id] = mi2[id] = lzy1[id];
sum[id] = lzy1[id] * (r - l + 1);
lzy1[id] = -1;lzy2[id] = 0;
}
else if(lzy2[id])
{
if(l != r)
{
if(~lzy1[id<<1]) put_down(id<<1,l,l+r>>1);
if(~lzy1[id<<1|1]) put_down(id<<1|1,(l+r>>1) + 1,r);
lzy2[id<<1] += lzy2[id];
lzy2[id<<1|1] += lzy2[id];
}
mx2[id] += mx1[id] * lzy2[id];
mi2[id] += mi1[id] * lzy2[id];
sum[id] += tot[id] * lzy2[id];
lzy2[id] = 0;
}
}
void modify(int id,int l,int r,ll num,ll k)
{
if(mi1[id] * num + mi2[id] >= k)
{
mi2[id] = k; mx2[id] = k;
sum[id] = k * (r - l + 1);
if(l != r)
{
lzy1[id<<1] = k;
lzy1[id<<1|1] = k;
}
return ;
}
if(mx1[id] * num + mx2[id] <= k)
{
if(l!= r)
{
if(~lzy1[id<<1]) put_down(id<<1,l,l+r>>1);
if(~lzy1[id<<1|1]) put_down(id<<1|1,(l+r>>1) + 1,r);
}
mi2[id] += num * mi1[id];
mx2[id] += num * mx1[id];
sum[id] += num * tot[id];
if(l != r)
{
lzy2[id<<1] += num;
lzy2[id<<1|1] += num;
}
return ;
}
if(l == r)
{
mi2[id] = mx2[id] = min(1ll*k,mi2[id] + mi1[id] * num);
sum[id] = mi2[id];
return;
}
int mid = l + r >> 1;
put_down(id<<1,l,mid); put_down(id<<1|1,mid + 1,r);
modify(id<<1,l,mid,num,k); modify(id<<1|1,mid + 1,r,num,k);
mi2[id] = min(mi2[id<<1],mi2[id<<1|1]);
mx2[id] = max(mx2[id<<1],mx2[id<<1|1]);
sum[id] = sum[id<<1] + sum[id<<1|1];
}
ll query(int id,int l,int r,ll num,ll k)
{
if(mx1[id] * num + mx2[id] < k) return 0;
if(mi1[id] * num + mi2[id] >= k) return sum[id] + tot[id] * num - (r - l + 1) * k;
if(l == r) return max(1ll*0,mx2[id] + mx1[id] * num - k);
int mid = l + r >> 1;
put_down(id<<1,l,mid); put_down(id<<1|1,mid + 1,r);
return query(id<<1,l,mid,num,k) + query(id<<1|1,mid + 1,r,num,k);
}
}seg;
int main()
{
// init("grass");
read(n); read(m);
rep(i,1,n) read(a[i]);
sort(a + 1,a + 1 + n);
seg.build(1,1,n);
ll d,b,lst=0;
while(m--)
{
read(d); read(b);
printf("%lld\n",seg.query(1,1,n,d - lst,b));
seg.modify(1,1,n,d - lst,b);
lst = d;
}
return 0;
}

本文详细解析了一道在成都进行的考试中出现的线段树题目,该题目要求利用线段树来维护区间信息,并提供了完整的 C++ 代码实现。通过本解析可以了解线段树的基本应用及其在区间更新和查询上的高效处理方法。
226

被折叠的 条评论
为什么被折叠?



