博客食用更佳bossbaby's blog
思路
线段树
直接线段树维护啊qwq
代码
#include
#define lid id<<1
#define rid id<<1|1
#define MAXN 1000010
#define LL long long
using namespace std;
struct SEG{
int l,r;
LL minn,lazy;
}tr[MAXN<<2];
LL a[1000010];
int n,m;
void pushup(int id){
tr[id].minn=min(tr[lid].minn,tr[rid].minn);
}
void pushnow(int id,int v){
tr[id].lazy+=v;
tr[id].minn+=v;
}
void pushdown(int id){
if(tr[id].lazy){
pushnow(lid,tr[id].lazy);
pushnow(rid,tr[id].lazy);
tr[id].lazy=0;
}
}
void build(int id,int l,int r){
tr[id].l=l,tr[id].r=r;
if(l==r){
tr[id].minn=a[l];
tr[id].lazy=0;
return;
}
int mid=(l+r)>>1;
build(lid,l,mid);
build(rid,mid+1,r);
pushup(id);
}
void update(int id,int l,int r,LL v){
pushdown(id);
if(tr[id].l>=l&&tr[id].r<=r){
pushnow(id,v);
return;
}
int mid=(tr[id].l+tr[id].r)>>1;
if(l<=mid)
update(lid,l,r,v);
if(r>=mid+1)
update(rid,l,r,v);
pushup(id);
}
LL query(int id,int l,int r){
pushdown(id);
if(tr[id].l>=l&&tr[id].r<=r){
return tr[id].minn;
}
int mid=(tr[id].l+tr[id].r)>>1;
LL ans=LLONG_MAX;
if(l<=mid)
ans=min(ans,query(lid,l,r));
if(r>=mid+1)
ans=min(ans,query(rid,l,r));
return ans;
}
int main(){
cin>>n>>m;
for(int i=1;i<=n;i++)cin>>a[i];
build(1,1,n);
for(int i=1;i<=n;i++){
LL d,s,t;
cin>>d>>s>>t;
if(query(1,s,t) 以上是假的
洛谷吸氧90
思路
二分
二分在何时不行,前缀和差分维护
代码
#include
#define MAXN 1000010
#define LL long long
using namespace std;
LL a[MAXN],d[MAXN],c[MAXN],sum[MAXN];
int n,m,s[MAXN],t[MAXN];
bool check(int x){
memset(c,0,sizeof(c));
for(int i=1;i<=x;i++){
c[s[i]]+=d[i];
c[t[i]+1]-=d[i];
}
for(int i=1;i<=n;i++){
sum[i]=sum[i-1]+c[i];
if(sum[i]>a[i])return 0;
}
return 1;
}
int main(){
cin>>n>>m;
for(int i=1;i<=n;i++)cin>>a[i];
for(int i=1;i<=n;i++)cin>>d[i]>>s[i]>>t[i];
int l=1,r=m;
if(check(m)){cout<<0<>1;
if(check(mid))l=mid+1;
else r=mid;
}
cout<<-1<