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#include<cstdio>
#include<ctype.h>
namespace ZDY{
    #pragma GCC optimize(3)
    #pragma GCC target("sse,sse2")
    #define il inline
    #define rg register
    #define ll long long
    #define db double
    #define sht short
    #define MB template <class T>
    #define Fur(i,x,y) for(rg int i=x;i<=y;i++)
    #define Fdr(i,x,y) for(rg int i=x;i>=y;i--)
    #define clr(x,y) memset(x,y,sizeof(x))
    #define cpy(x,y) memcpy(x,y,sizeof(x))
    #define fin(s) freopen(s".in","r",stdin)
    #define fout(s) freopen(s".out","w",stdout)
    #define l2(n) (int(log2(n)))
    #define inf 2000000000
    #define fl(i,x) for(rg int i=head[x],to;to=e[i].to,i;i=e[i].nxt)
    #define fcin ios::sync_with_stdio(false)
    MB T ABS(T x){return x>0?x:-x;}
    MB T MAX(T x,T y){return x>=y?x:y;}
    MB T MIN(T x,T y){return x<=y?x:y;}
    MB T GCD(T x,T y){return y?GCD(y,x%y):x;}
    void SWAP(int &x,int &y){x^=y;y^=x;x^=y;}
}using namespace ZDY;using namespace std;
namespace IO{const char* ln="\n";const int str=1<<20;struct IN{char buf[str],*s,*t;bool _;IN():s(buf),t(buf),_(0){}il char gc(){return s==t&&((t=(s=buf)+fread(buf,1,str,stdin))==s)?EOF:(*s++);}IN&operator>>(char&ch){if(_)return *this;char c;while((c=gc())!=EOF&&isspace(c));if(c==EOF)_=1;else ch=c;return *this;}IN& operator>>(char* ch){if(_)return *this;char c;while((c=gc())!=EOF&&isspace(c));if(c==EOF)return _=1,*this;*ch=c;ch++;while((c=gc())!=EOF&&!isspace(c))*ch=c,ch++;if(c==EOF)_=1;return *this;}template<typename T>IN&operator>>(T&x){if(_)return *this;char c=gc();bool ff=0;while(c!=EOF&&(c<'0'||c>'9'))ff^=(c=='-'),c=gc();if(c==EOF){_=1;return *this;}x=0;while(c!=EOF&&'0'<=c&&c<='9')x=(x<<3)+(x<<1)+c-48,c=gc();if(c==EOF)_=1;if(ff)x=-x;return *this;}}in;struct OUT{char buf[str],*s,*t;OUT():s(buf),t(buf+str){}~OUT(){fwrite(buf,1,s-buf,stdout);}void pt(char c){(s==t)?(fwrite(s=buf,1,str,stdout),*s++=c):(*s++=c);}OUT&operator<<(const char*s){while(*s)pt(*s++);return *this;}OUT&operator<<(char*s){while(*s)pt(*s++);return *this;}template<typename T>OUT&operator<<(T x){if(!x)return pt('0'),*this;if(x<0)pt('-'),x=-x;char a[30],t=0;while(x)a[t++]=x%10,x/=10;while(t--)pt(a[t]+'0');return *this;}}out;}using namespace IO;
#define N 50011
int n,q,s[N<<2],S[N<<2],L[N<<2],R[N<<2];
struct tr{int s,S,L,R;}t[N<<2];
#define Z int m=(l+r)>>1
#define ls rt<<1
#define rs rt<<1|1
void pu(int rt){
    t[rt].s=t[ls].s+t[rs].s;
    t[rt].S=MAX(MAX(MAX(t[ls].R,t[rs].L),t[ls].R+t[rs].L),MAX(t[ls].S,t[rs].S));
    t[rt].L=MAX(t[ls].L,t[ls].s+t[rs].L);t[rt].R=MAX(t[rs].R,t[rs].s+t[ls].R);
}
void build(int l,int r,int rt){
    if(l==r){
        in>>t[rt].s;t[rt].L=t[rt].R=t[rt].S=t[rt].s;
        return;
    }
    Z;
    build(l,m,ls);build(m+1,r,rs);
    pu(rt);
}
void upd(int x,int v,int l,int r,int rt){
    if(l==r){t[rt].s=t[rt].S=t[rt].R=t[rt].L=v;return;}
    Z;
    if(x<=m)upd(x,v,l,m,ls);
    else upd(x,v,m+1,r,rs);
    pu(rt);
}
tr ask(int x,int y,int l,int r,int rt){
    if(x<=l&&r<=y)return t[rt];
    Z;
    if(x>m)return ask(x,y,m+1,r,rs);
    if(y<=m)return ask(x,y,l,m,ls);
    tr ans,a=ask(x,y,l,m,ls),b=ask(x,y,m+1,r,rs);
    ans.s=a.s+b.s;
    ans.S=MAX(MAX(MAX(a.R,b.L),a.R+b.L),MAX(a.S,b.S));
    ans.L=MAX(a.L,a.s+b.L);ans.R=MAX(b.R,b.s+a.R);
    return ans;
}
int main(){
    fin("in");
    in>>n>>q;
    build(1,n,1);
    while(q--){
        int u,l,r;in>>u>>l>>r;
        if(l>r)SWAP(l,r);
        if(u==1)out<<ask(l,r,1,n,1).S<<ln;
        else upd(l,r,1,n,1);
    }
}
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