2015 Multi-University Training Contest 3 hdu 5316 Magician

Magician

Time Limit: 18000/9000 MS (Java/Others) Memory Limit: 65536/65536 K (Java/Others)
Total Submission(s): 543 Accepted Submission(s): 151


[align=left]Problem Description[/align]
Fantasy magicians usually gain their ability through one of three usual methods: possessing it as an innate talent, gaining it through study and practice, or receiving it from another being, often a god, spirit, or demon of some sort. Some wizards are depicted as having a special gift which sets them apart from the vast majority of characters in fantasy worlds who are unable to learn magic.

Magicians, sorcerers, wizards, magi, and practitioners of magic by other titles have appeared in myths, folktales, and literature throughout recorded history, with fantasy works drawing from this background.

In medieval chivalric romance, the wizard often appears as a wise old man and acts as a mentor, with Merlin from the King Arthur stories representing a prime example. Other magicians can appear as villains, hostile to the hero.

#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
const LL INF = 0x3f3f3f3f3f3f3f3f;
const int maxn = 100010;
struct node{
LL a,b,c,d;
//分别代表奇奇、奇偶、偶偶、偶奇
}tree[maxn<<2];
void pushup(node &z,const node &x,const node &y){
z.a = max(x.a,y.a);
z.a = max(z.a,x.a + y.d);
z.a = max(z.a,x.b + y.a);
z.b = max(x.b,y.b);
z.b = max(z.b,x.b + y.b);
z.b = max(z.b,x.a + y.c);
z.c = max(x.c,y.c);
z.c = max(z.c,x.c + y.b);
z.c = max(z.c,x.d + y.c);
z.d = max(x.d,y.d);
z.d = max(z.d,x.c + y.a);
z.d = max(z.d,x.d + y.d);
}
void build(int lt,int rt,int v){
if(lt == rt){
LL tmp;
scanf("%I64d",&tmp);
if(lt&1){
tree[v].a = tmp;
tree[v].b = tree[v].c = tree[v].d = -INF;
}else{
tree[v].c = tmp;
tree[v].a = tree[v].b = tree[v].d = -INF;
}
return;
}
int mid = (lt + rt)>>1;
build(lt,mid,v<<1);
build(mid+1,rt,v<<1|1);
pushup(tree[v],tree[v<<1],tree[v<<1|1]);
}
void update(int L,int R,int lt,int rt,LL val,int v){
if(lt <= L &&  rt >= R){
if(lt&1){
tree[v].a = val;
tree[v].b = tree[v].c = tree[v].d = -INF;
}else{
tree[v].c = val;
tree[v].a = tree[v].b = tree[v].d = -INF;
}
return;
}
int mid = (L + R)>>1;
if(lt <= mid) update(L,mid,lt,rt,val,v<<1);
if(rt > mid) update(mid+1,R,lt,rt,val,v<<1|1);
pushup(tree[v],tree[v<<1],tree[v<<1|1]);
}
node query(int L,int R,int lt,int rt,int v){
if(lt == L && rt == R) return tree[v];
int mid = (L + R)>>1;
if(rt <= mid) return query(L,mid,lt,rt,v<<1);
else if(lt > mid) return query(mid+1,R,lt,rt,v<<1|1);
else{
node x = query(L,mid,lt,mid,v<<1);
node y = query(mid+1,R,mid+1,rt,v<<1|1);
node z;
pushup(z,x,y);
return z;
}
}
int main(){
int kase,n,m,op,x,y;
LL val;
scanf("%d",&kase);
while(kase--){
scanf("%d%d",&n,&m);
build(1,n,1);
while(m--){
scanf("%d%d",&op,&x);
if(!op){
scanf("%d",&y);
node ret = query(1,n,x,y,1);
printf("%I64d\n",max(max(ret.a,ret.b),max(ret.c,ret.d)));
}else{
scanf("%I64d",&val);
update(1,n,x,x,val,1);
}
}
}
return 0;
}

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