线段树写得很少，这么基本的算法还是要会的……
#include<bits/stdc++.h> using namespace std; inline long long read() { long long x = 0, f = 1; char ch = getchar(); while (ch<'0' || ch>'9') { if (ch == '-') f = -1;ch = getchar(); } while (ch >= '0'&&ch <= '9') { x = x * 10 + ch - '0';ch = getchar(); } return x*f; } const int maxn = 131071; int n,m,op,_l,_r,k; struct NODE{ int l,r; long long lazy,val; }node[maxn<<2]; void pushup(int rt){ node[rt].val = node[rt<<1].val+node[rt<<1|1].val; } void pushdown(int rt){ if(!node[rt].lazy) return ; int mid = node[rt].l+node[rt].r >>1; node[rt<<1].lazy += node[rt].lazy; node[rt<<1|1].lazy += node[rt].lazy; node[rt<<1].val += node[rt].lazy*(mid-node[rt].l+1); node[rt<<1|1].val += node[rt].lazy*(node[rt].r-mid); node[rt].lazy = 0; } void build(int x,int l,int r){ if((node[x].l = l) == (node[x].r = r)) return; int mid = node[x].l+node[x].r>>1; build(x<<1,l,mid),build(x<<1|1,mid+1,r); } //单点更新 void add_one(int rt,int pos,long long val){ if(node[rt].l == node[rt].r){ node[rt].val+=val; return; } int mid = node[rt].l+node[rt].r>>1; add_one(rt<<1|pos>mid,pos,val); pushup(rt); } //区域更新 //所谓lazy就是只有当需要pushdown时才pushdown，query同 void add(int rt,int l,int r,int val){ pushdown(rt); // 这一行的作用见 https://jecvay.com/2014/11/segment-tree-lazy-design.html if(node[rt].l>=l && node[rt].r<=r){ node[rt].val+=val*(node[rt].r-node[rt].l+1); node[rt].lazy += val; return ; } int mid = node[rt].l+node[rt].r>>1; if(l<=mid) add(rt<<1,l,r,val); if(r>mid) add(rt<<1|1,l,r,val); pushup(rt); } long long query(int rt,int l,int r){ pushdown(rt); if(node[rt].l>=l && node[rt].r<=r) return node[rt].val; int mid = node[rt].l + node[rt].r >> 1; long long ans = 0; if(l<=mid) ans+=query(rt<<1,l,r); // 易错 if(r>mid) ans+=query(rt<<1|1,l,r); return ans; } int main(){ n = read(), m = read(); build(1,0,n); for(int i = 0;i<n;i++) add_one(1,i,read()); for(int i = 0;i<m;i++){ op = read();_l = read()-1; _r = read()-1; if(op-1) printf("%lld ",query(1,_l,_r)); else{ k = read(); add(1,_l,_r,k); } } return 0; }