线段树区间增加/赋值 求区间和最大值最小值

/*
maxnode为区间长度的三倍
调用：
tree.update(1, 1, n);
tree.query(1, 1, n, 0);
n为区间长度,[y11, y22]为维护或查询区间,v为增加值或修改值
op == 1时区间加上v,op == 2时区间修改为v
*/
const int maxnode = 100000 * 3;
int _sum, _min, _max, op, y11, y22, v;
struct IntervalTree {
  int sumv[maxnode], minv[maxnode], maxv[maxnode], setv[maxnode], addv[maxnode];

  // 维护信息
  void maintain(int o, int L, int R) {
    int lc = o*2, rc = o*2+1;
    if(R > L) {
      sumv[o] = sumv[lc] + sumv[rc];
      minv[o] = min(minv[lc], minv[rc]);
      maxv[o] = max(maxv[lc], maxv[rc]);
    }
    if(setv[o] >= 0) { minv[o] = maxv[o] = setv[o]; sumv[o] = setv[o] * (R-L+1); }
    if(addv[o]) { minv[o] += addv[o]; maxv[o] += addv[o]; sumv[o] += addv[o] * (R-L+1); }
  }

  // 标记传递
  void unmark(int o) {
    int lc = o*2, rc = o*2+1;
    if(setv[o] >= 0) {
      setv[lc] = setv[rc] = setv[o];
      addv[lc] = addv[rc] = 0;
      setv[o] = -1; // 清除本结点标记
    }
    if(addv[o]) {
      addv[lc] += addv[o];
      addv[rc] += addv[o];
      addv[o] = 0; // 清除本结点标记
    }
  }

  void update(int o, int L, int R) {
    int lc = o*2, rc = o*2+1;
    if(y11 <= L && y22 >= R) { // 标记修改
      if(op == 1) addv[o] += v;
      else { setv[o] = v; addv[o] = 0; }
    } else {
      unmark(o);
      int M = L + (R-L)/2;
      if(y11 <= M) update(lc, L, M); else maintain(lc, L, M);
      if(y22 > M) update(rc, M+1, R); else maintain(rc, M+1, R);
    }
    maintain(o, L, R);
  }

  void query(int o, int L, int R, int add) {
    if(setv[o] >= 0) {
      int v = setv[o] + add + addv[o];
      _sum += v * (min(R,y22)-max(L,y11)+1);
      _min = min(_min, v);
      _max = max(_max, v);
    } else if(y11 <= L && y22 >= R) {
      _sum += sumv[o] + add * (R-L+1);
      _min = min(_min, minv[o] + add);
      _max = max(_max, maxv[o] + add);
    } else {
      int M = L + (R-L)/2;
      if(y11 <= M) query(o*2, L, M, add + addv[o]);
      if(y22 > M) query(o*2+1, M+1, R, add + addv[o]);
    }
  }
} tree;